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METEORITES 


THEIR   STRUCTURE,    COMPOSITION,    AND 
TERRESTRIAL   RELATIONS 


BY 

OLIVER  CUMMINGS  JPARRINGTON,  Ph.D. 

CURATOR  OF  GEOLOGY 
FIELD  MUSEUM  OF  NATURAL  HISTORY 


CHICAGO,  U.  S.  A. 
1915 

PUBLISHED  BY  THE  AUTHOR 


COPYRIGHT,  1915 
O.  C.  FARRINGTON 


R.  R.  DONNELLEY  &  SONS  COMPANY 
CHICAGO 


BAtTH 


PREFACE 

Three  reasons  may  be  assigned  for  ascribing  peculiar 
interest  to  the  study  of  meteorites: 

First.  They  are  our  only  tangible  sources  of  knowledge 
regarding  the  universe  beyond  us. 

Second.     They  are  portions  of  extra-terrestrial  bodies. 

Third.  They  are  a  part  of  the  economy  of  Nature.  No 
survey  of  Nature  can  be  considered  complete  which  does  not 
include  an  account  of  them. 

For  these  and  other  reasons,  the  writer  has  long  experi- 
enced a  fascination  and  delight  in  the  study  of  these  bodies. 
In  seeking  works  for  his  guidance,  however,  he  has  found  a 
lamentable  lack  of  any  which  treated  the  subject  comprehen- 
sively. While  some  phases  of  the  subject  and  the  character- 
istics of  many  individual  falls  have  been  investigated  with 
admirable  thoroughness,  the  subject  as  a  whole  has  not 
received  extensive  treatment.  The  admirable  Meteoriten- 
kunde  of  Cohen  would  have  left  little  to  be  desired  had  its 
author  been  permitted  to  carry  out  his  broadly  conceived 
plan,  but  this  privilege  was  unfortunately  denied  him. 
Meunier's  Meteorites  has  not  been  revised  in  recent  years 
and  Fletcher's  Introduction,  while  a  model  of  its  kind,  is 
limited  in  its  scope.  That  the  present  writer  has  been 
greatly  assisted  by  the  above  works  and  many  others  in 
the  preparation  of  this  one  needs  hardly  to  be  stated. 
Detailed  references  to  these  works,  however,  were  deemed 
to  be  impracticable  except  where  it  was  thought  that  a 
fuller  treatment  of  certain  subjects  might  be  desired  by 
some  readers.  In  such  cases  references  have  been  given. 

Much  assistance  in  the  preparation  of  illustrations  for 
this  work  was  given  the  writer  by  the  late  Prof.  Henry  A. 
Ward.  Mr.  D.  M.  Barringer  generously  furnished  photo- 
graphs of  Meteor  Crater,  Arizona,  and  the  writer  is  indebted 
to  the  Journal  of  Geology  through  its  editor,  Prof.  T.  C. 
Chamberlin,  for  the  loan  of  several  cuts. 


S31086 


TABLE  OF  CONTENTS 

CHAPTER  Page 

I.     GENERAL  CHARACTERS  AND  NOMENCLATURE  .        i 

II.     PHENOMENA  OF  FALL j 

III.  GEOGRAPHICAL  DISTRIBUTION  OF  METEORITJES     34 

IV.  TIMES  OF  FALL ^ 

V.     SHOWERS 46 

VI.     SIZE  OF  METEORITES 54 

VII.     FORMS  OF  METEORITES   ...  60 

VIII.     CRUST    ....  78 

IX.     VEINS .'      .      85 

X.     STRUCTURE  OF  METEORITES 92 

a.  IRONS 92 

b.  IRON-STONES       .      .      .      ...      .      .    IQI 

c.  STONES .  IO2 

XI.     COMPOSITION  OF  METEORITES 113 

XII.     CLASSIFICATION j<^ 

XIII.  ORIGIN ' .  .    .         205 

XIV.  TERRESTRIAL  RELATIONS 214 

XV.     METEORITE  COLLECTIONS      .      .  220 


Vll 


LIST  OF  ILLUSTRATIONS 

PAGE 

THE  BACUBIRITO,  MEXICO,  METEORITE Frontispiece 

Fig.    i.     FALL  OF  THE  TABORY  METEORITE 8 

"      2.     FALL  OF  THE  AGRAM  METEORITE n 

3.  FALL  OF  THE  KNYAHINYA  METEORITE 15 

4.  HOLE  MADE  BY  THE  ST.  MICHEL  METEORITE 22 

5.  METEOR  CRATER,  ARIZONA 24 

6.  CRATERS  OF  THE  MOON ...  26 

7.  OLD  DRAWING  PERHAPS  REPRESENTING  A  FALL  OF  METEORITES  28 

8.  DIAGRAM  SHOWING  EFFECT  OF  OBSERVER'S  POSITION  ON  APPARENT 

PATHS  OF  METEORS 32 

9.  CURVE  OF  METEORITE  FALLS  BY  MONTHS 39 

10.  CURVE  OF  METEORITE  FALLS  BY  HOURS      ...           ...  42 

11.  DIAGRAM  SHOWING  RELATION  OF  TIME  OF  DAY  TO  VELOCITIES 

OF  METEORITES 43 

12.  DISTRIBUTION  OF  INDIVIDUALS  OF  THE   HOMESTEAD  METEORITE 

SHOWER 47 

13.  INDIVIDUALS  OF  THE  ORGUEIL,  FRANCE,  METEORITE    SHOWER     .  51 

14.  THE  CAPE  YORK,  GREENLAND  METEORITE 54 

15.  THE  WILLAMETTE,  OREGON,  METEORITE 56 

16.  EL  MORITO,  MEXICO,  METEORITE 57 

17.  DIAGRAM  SHOWING  DEVELOPMENT  OF  CONICAL  FORM       .      .      .  61 

18.  FRONT  AND  REAR  SIDES  OF  CABIN  CREEK  METEORITE   ....  62 

19.  FRONT  SIDE  OF  GOALPARA  METEORITE 63 

'    20.    THE  JONZAC  METEORITE     .           64 

'    21.     SIDE  VIEW  OF  WILLAMETTE  METEORITE       .......  65 

'     22.     THE  LONG  ISLAND  METEORITE            66 

1     23.     SIDE  AND  FRONT  VIEWS  OF  THE  BATH  FURNACE  METEORITE     .  67 

'     24.     FRONT  AND  SIDE  VIEWS  OF  THE  ALGOMA  METEORITE       ...  69 

'     25.     CHARLOTTE  AND  BOOGALDI  METEORITES 71 

1     26.     FRONT  END  OF  THE  BOOGALDI  METEORITE 72 

1    27.     ETCHED  SECTION  OF  THE  BOOGALDI  METEORITE 73 

1     28.     THE  BABE'S  MILL    METEORITE           .  • 74 

'    29.    THE  TUCSON  METEORITE 75 

30.  THE  HEX  RIVER  AND  KOKSTAD  METEORITES 76 

31.  CRUST  OF  THE  CHARLOTTE  METEORITE 79 

32.  SURFACE  OF  THE  JUNCAL  METEORITE 80 

33.  MICROSCOPIC  SECTION  OF  CRUST  OF  Mocs  METEORITE    ...  82 

34.  ENLARGED  VIEW  OF  VEIN  OF  Mocs  METEORITE 86 

35.  SLICKENSIDED  SURFACE  OF  LONG  ISLAND  METEORITE       ...  90 

36.  ETCHING  FIGURES  OF  THE  RED  RIVER  METEORITE      ....  93 

37.  ETCHING  FIGURES  PARALLEL  TO  AN  OCTAHEDRAL  FACE    ...  94 

38.  ETCHING  FIGURES  PARALLEL  TO  A  CUBIC  FACE 94 

39.  ETCHING  FIGURES  PARALLEL  TO  A  DODECAHEDRAL  FACE       .      .  94 

40.  ETCHING  FIGURES  PARALLEL  TO  AN  ASYMMETRICAL  FACE      .      .  94 

41.  TESSELATED  OCTAHEDRAL  FIGURES 96 

42.  DIAGRAM  OF  ETCHING  FIGURES  OF  A  CUBIC  METEORITE       .      .  97 

43.  ETCHING  FIGURES  OF  A  TOLUCA  METEORITE  BEFORE  AND  AFTER 

HEATING 99 

44.  CHONDRI  OF  THE  HOMESTEAD  METEORITE  AS  SEEN  UNDER  THE 

MICROSCOPE- 104 

ix 


x  LIST  OF   ILLUSTRATIONS 

Fig.  45.     LARGE  CHONDRUS  ENCLOSING  A  SMALL  ONE  AS  SEEN  UNDER  THE 

MICROSCOPE 106 

'    46      MICROSCOPIC  SECTION  OF  THE  MEZO  MADARAS  METEORITE        .  107 

'     47.     DRAWING  OF  PYRRHOTITE  CRYSTAL  FROM  THE  JUVINAS  METEORITE  142 

'    48.     REICHENBACH  LAMELLAE 143 

1    49.     PERFORATED  CANYON  DIABLO  METEORITE 144 

50.  BREZINA'S  LAMELLAE 150 

51.  DRAWINGS  OF  ANORTHITE  CRYSTALS  FROM  THE  JUVINAS  METEORITE  167 

52.  DRAWING  OF    AN    ENSTATITE    CRYSTAL    FROM    THE    STEINBACH 

METEORITE 172 

53.  DRAWING  OF   AN    ENSTATITE    CRYSTAL    FROM    THE    STEIN  RACK 

METEORITE 172 

54.  DRAWING  OF  A  DIOPSIDE?  CRYSTAL  FROM  THE  JUVINAS  METEORITE  179 

55.  DRAWING  OF  AN  AUGITE  CRYSTAL  FROM  THE  JUVINAS  METEORITE  180 

56.  FORMS  OF  CHRYSOLITE  FROM  THE  PALLAS  METEORITE      ...  182 

57.  COMMON  FORMS  OF  METEORITIC  CHRYSOLITE 183 

58.  TYPICAL  ARRANGEMENTS  OF  CHRYSOLITE  LAMELLAE    ....  184 

59.  EFFECT   OF    EARTH'S    GRAVITATION    ON    BODIES    OF    DIFFERENT 

VELOCITIES 207 

'  60.  DANIEL'S  COMET 209 

'  61.  A  SHOOTING  STAR  TRAIL  SHOWING  INCREASE  IN  BRIGHTNESS  .  210 

'  62.  THE  PLANET  SATURN  AND  ITS  RINGS 212 

'  63.  MOVING  THE  CAPE  YORK  METEORITE  IN  NEW  YORK  CITY  .  .221 
'  64.  TOWN  HALL  AT  ELBOGEN,  BOHEMIA,  IN  WHICH  A  METEORITE  HAS 

HUNG  FIVE  CENTURIES 222 

'  65.  METEORITE  COLLECTION  OF  THE  FIELD  MUSEUM  OF  NATURAL 

HISTORY 224 


METEORITES 


CHAPTER  I 

GENERAL  CHARACTERS  AND   NOMENCLATURE 

Meteorites  are  solid  bodies  which  come  to  the  earth  from 
space.  Their  dimensions  range  from  microscopic  to  many 
cubic  feet.  Their  fall  to  the  earth  is  usually  marked  by 
peculiar  phenomena  of  sound  and  light.  The  masses 
observed  to  fall  are  for  the  most  part  of  a  stony  nature, 
granular,  of  a  grayish  color,  and  covered  with  a  thin,  black 
crust.  As  a  rule,  they  contain  particles  of  metal  scattered 
through  their  substance.  In  the  material  of  some  falls 
the  metal  more  largely  predominates  and  still  others  are 
made  up  wholly  of  metal.  The  nature  of  this  metal  is 
essentially  similar  in  all  meteorites,  being  iron  alloyed  with 
from  five  to  twenty-five  per  cent  of  nickel. 

According  to  their  prevailing  substance  meteorites  may 
be  divided  into  the  two  classes  of  stone  and  iron  meteorites. 
It  is  convenient  also  at  times  to  distinguish  an  intermediate 
class  which  may  be  designated  as  iron-stone  meteorites. 

Most  stone  meteorites,  as  has  been  said,  have  the  appear- 
ance of  a  grayish  mass  covered  with  a  black,  more  or  less 
shining  crust.  Occasionally 'the  mass  of  the  stone  may 
be  so  dark  as  to  be  practically  black  or  it  may  be  brownish. 
Again  it  may  be  nearly  white.  Further,  the  crust  does  not 
always  differ  in  color  from  the  interior,  especially  in  the  case 
of  brown  or  black  meteorites.  Scattered  metallic  grains 
usually  characterize  the  substance  of  stone  meteorites. 
The  coherence  of  the  stone  meteorites  is  usually  such  that 
they  do  not  break  easily  under  the  blow  of  a  hammer  and 
they  take  a  fair  polish.  Some  can,  however,  be  crumbled 
in  the  fingers. 

The  iron-stone  meteorites  differ  chiefly  from  the  stone 


2  ;  :  •'     METEORITES 

m^teorkcs  in  their  abundance  in  metal.  Instead  of  occur- 
ring as  minute,  scattered  grains  forming  but  a  small  per- 
centage of  the  mass  of  the  meteorite,  the  metal  makes  up 
about  half  the  mass  and  is  often  continuous.  Single  nodules 
of  the  metal  may  reach  a  diameter  of  one  inch  or  more. 
Further,  the  metal  may  be  so  abundant  as  to  form  a  matrix 
of  a  sponge-like  character  in  the  pores  of  which  silicates  are 
held.  Thus  by  gradation  the  iron-stone  meteorites  pass  to 
meteorites  made  up  entirely  of  metal  or  iron  meteorites. 

The  metal  of  the  iron  meteorites  is,  when  fresh,  of  a 
silver-white  to  grayish-white  color  and  usually  malleable. 
It  is  made  up,  as  has  been  said,  chiefly  of  iron  alloyed  with 
from  five  to  twenty-five  per  cent  of  nickel.  When  found 
immediately  upon  falling,  meteorites  of  this  composition 
usually  exhibit  a  blackish  or  bluish  crust  through  which  the 
silvery  appearing  interior  gleams  here  and  there,  but  any 
continued  exposure  usually  causes  the  entire  surface  of  such 
meteorites  to  become  of  a  rusty-brown  color. 

No  single  criterion  can  be  given  for  distinguishing  mete- 
orites from  masses  of  terrestrial  origin.  Only  by  combining 
several  features  can  the  positive  determination  of  a  meteorite 
be  made.  A  pitted  and  fused  surface  is  an  important  char- 
acter of  meteorites,  yet  on  the  one  hand  this  may  not  be 
present  and  the  body  be  meteoric,  and  on  the  other  hand 
very  similar  pittings,  though  not  often  produced  by  fusion, 
may  be  observed  on  terrestrial  rocks.  The  presence  of 
metallic  grains  is  generally  a  distinctive  feature  of  stone 
meteorites,  but  these  grains  are  lacking  in  some  meteorites, 
and  a  somewhat  similar  appearance  through  the  presence 
of  scattered  grains  of  pyrite  or  other  mineral  of  metallic 
luster,  may  be  seen  in  terrestrial  rocks.  The  true  chondritic 
structure  when  observed  under  the  microscope  may  be 
considered  a  decisive  mark  of  a  meteorite,  yet  a  few  mete- 
orites do  not  have  this  structure. 

So  far  as  the  iron  meteorites  are  concerned  the  presence  of 
nickel  is  essential.  No  iron  meteorites  are  known  without 
nickel.  Yet  this  alone  does  not  prove  meteoric  origin  since 
terrestrial  nickel-irons  are  known.  Terrestrial  nickel-irons, 
however,  have  a  percentage  of  nickel  either  lower  (3  per 


GENERAL   CHARACTERS   AND   NOMENCLATURE    3 

cent)  or  higher  (35  percent)  than  that  of  meteorites,  so  that 
a  percentage  of  nickel  between  8  per  cent  and  20  per  cent  is 
a  pretty  sure  indication  of  meteoric  origin.  The  exhibition 
of  octahedral  figures  on  etching  is  a  character  confined  to  iron 
meteorites,  yet  a  metallic  mass  may  be  a  meteorite  and  not 
give  these  figures.  A  pitted  surface  is  characteristic  of  iron 
as  well  as  of  stone  meteorites,  but  this  may  be  destroyed  by 
weathering;  so  that  its  absence  is  not  a  sure  indication  of 
terrestrial  origin.  To  recapitulate:  Stone  meteorites  usually 
show  a  pitted  and  fused  surface,  differing  in  color  from  the 
interior  and  the  interior  usually  contains  scattered  metallic 
grains.  Iron  meteorites  always  contain  nickel,  usually  ex- 
hibit a  pitted  surface,  and  frequently  show  octahedral  bands 
on  an  etched  surface.  A  convenient  test  for  nickel  in  a  mass 
whose  meteoric  origin  is  suspected  may  be  made  by  dissolv- 
ing a  fragment  of  the  substance  to  be  tested  in  nitric  acid, 
adding  ammonia  till  the  acid  is  neutralized,  boiling,  add- 
ing a  little  more  ammonia  to  make  sure  that  all  the  iron 
has  been  precipitated  and  filtering  off  this  precipitate  (ferric 
hydroxide).  If  the  filtrate  shows  a  bluish  tinge  the  presence 
of  nickel  is  indicated,  but  as  small  amounts  of  nickel  might 
not  be  indicated  in  this  way  a  few  drops  of  yellow  ammonium 
sulphide  should  be  added  to  the  cold,  clear  filtrate.  If  nickel 
is  present,  a  black  precipitate  of  nickel  sulphide  will  be  ob- 
tained. In  order  to  test  this  further,  the  liquid  should  be 
filtered  and  the  precipitate  tested  with  a  borax  bead.  If 
nickel  is  present  a  violet  bead  will  be  obtained  in  the  oxidiz- 
ing flame,  changing  to  reddish  brown  on  cooling.  Another 
test  for  nickel  in  the  presence  of  iron  consists  of  dissolving 
the  substance  to  be  investigated  in  hydrochloric  acid,  boiling 
for  a  moment  with  a  few  drops  of  nitric  acid  to  oxidize  the 
iron,  adding  a  little  citric  or  tartaric  acid  to  prevent  pre- 
cipitation of  the  iron,  neutralizing  the  solution  with  am- 
monia and  adding  a  few  drops  of  a  solution  of  di-methyl 
gloxine  in  alcohol.  If  nickel  is  present  a  blood-red  color 
will  be  given  the  solution;  if  not,  no  change  of  color  will 
occur. 

Owing  to  the  characters  above  described  actual  observa- 
tion of  the  fall  of  a  meteorite  is  no  longer  necessary  in  order 


4  METEORITES 

to  establish  its  meteoric  origin.  In  fact,  the  internal 
characters  of  a  meteorite  furnish  at  the  present  time  much 
more  reliable  evidence  of  its  origin  than  does  as  a  rule  the 
testimony  of  human  witnesses.  Of  about  seven  hundred 
meteorites  now  recognized,  only  about  one-half  were  actually 
seen  to  fall.  It  has  been  more  or  less  customary  to  designate 
meteorites  seen  to  fall  as  "falls,"  while  those  determined 
from  internal  characters  were  called  "finds."  Since  all 
true  meteorites  fell  at  some  time,  however,  the  distinction 
seems  superfluous.  In  the  present  work  all  meteorites  are 
referred  to  as  falls,  the  distinctions  of  separate  falls  being 
based  on  separate  occurrence  in  time  or  place,  or  both. 

As  betwesn  stone  and  iron  meteorites,  it  may  be  remarked 
that  a  far  larger  number  of  stone  than  iron  meteorites  has 
been  observed  to  fall.  Of  about  350  observed  falls  only 
10  have  been  of  iron  meteorites.  On  the  other  hand, 
among  meteorite  "finds,"  the  iron  meteorites  largely 
predominate.  This  is  chiefly  for  the  reason,  doubtless,  that 
the  iron  meteorites  by  their  relatively  great  weight,  metallic 
resonance  and  internal  silvery  appearance  attract  the 
attention  of  the  ordinary  observer  much  more  quickly  than 
the  stone  meteorites.  The  latter  show  to  the  casual  ob- 
server no  striking  differences  from  terrestrial  rocks,  and  are 
thus  usually  overlooked. 

In  order  to  facilitate  the  comparison,  collection,  and  study 
of  different  falls  it  was  long  ago  found  desirable  to  give  each 
fall  a  name.  Various  methods  of  choosing  such  names 
have  been  adopted:  First,  and  most  commonly,  that  of  the 
province  or  region  where  the  fall  occurred  has  been  used. 
Second,  the  name  of  the  discoverer  has  been  applied.  Third, 
the  meteorite  has  been  named  from  some  peculiarity  of  its 
shape  or  size.  Illustrations  of  the  first  class  are  the  names 
Mexico,  Colorado,  Texas,  which  have  been  given  to  meteoric 
falls;  of  the  second  class,  Gibbs,  Lea,  Pallas,  Humboldt; 
and  of  the  third  class,  Signet,  Moon,  Woman.  Of  these 
methods  of  naming  the  fall,  that  of  employing  the  name 
of  the  place  has  been  found  most  satisfactory  and  has  come 
to  be  generally  adopted,  but  even  this  method  has  passed 
through  some  modifications.  When  but  few  meteorites  were 


GENERAL   CHARACTERS   AND   NOMENCLATURE    5 

known  it  was  sufficient  to  designate  one  as  Mexico,  another 
as  Colorado,  etc.,  but  after  two  or  more  meteorites  came  to 
be  known  from  the  same  state  or  country  this  method  of 
nomenclature  was  obviously  inadequate.  A  modification  of 
this  method  which  gained  some  adoption  was  that  of  giving 
successive  meteorites  from  the  same  state  or  province  serial 
numbers,  such  as  Colorado  I,  2,  3,  etc.,  but  this  was  long 
since  abandoned. 

For  the  most  part,  names  of  persons  or  descriptive  names 
that  have  been  applied  to  meteorites  are  now  also  changed 
to  names  which  show  localities.  Thus  the  Pallas  meteorite 
is  now  known  as  Krasnojarsk,  the  Ainsa  meteorite  as 
Tucson,  the  Lea  meteorite  as  Cleveland,  etc. 

Some  authorities,  such  as  Berwerth*  have  urged  that  the 
law  of  priority  should  govern  the  naming  of  meteorites  as 
it  does  that  of  some  other  objects.  This  would  require, 
however,  giving  a  number  of  meteorites  the  same  name  and 
destroy  in  many  cases  the  very  great  advantage  arising  from 
having  the  name  of  a  meteorite  express  the  locality  of  its 
fall. 

Accordingly  at  the  present  time  in  the  naming  of  a 
meteorite  the  plan  is  almost  universally  followed  of  desig- 
nating it  by  the  name  of  the  town  or  locality  of  prominence 
nearest  to  which  it  fell.  Thus  the  name  Castine,  for  in- 
stance, is  used  to  designate  the  meteorite  which  fell  at 
Castine,  Maine,  May  20,  1848. 

For  the  science  which  has  for  its  field  the  study  of  mete- 
orites, several  names  have  been  proposed,  but  none  have 
as  yet  received  general  adoption.  Shepard  suggested 
"astrolithology,"  meaning  lithology  of  the  stars,  but 
meteorites  are  now  considered  to  be  quite  distinct  from  the 
stars.  Maskelyne  proposed  "aerolitics, "  but  the  term 
refers  to  but  a  single  group  of  meteorites  according  to  a 
distinction  made  by  Maskelyne  himself.  By  using  the  term 
"meteoritics"  the  objection  mentioned  may  be  overcome 
and  this  name  may  in  time  gain  adoption.  The  science  of 
meteoritics  obviously  looks  to  many  other  sciences  for  its 

*  Verzeichnis  der  Meteoriten,  1902,  Ann.  d.  K.  K.  Naturhist.  Hof  Mus.,  Wien, 
Bd.  xviii,  pp.  2-3. 


6  METEORITES 

data  and  growth.  The  science  of  astronomy  throws  light 
on  the  relations  of  meteorites  to  the  other  heavenly  bodies; 
the  sciences  of  geology,  petrology,  and  mineralogy  elucidate 
the  relations  of  meteorites  to  the  earth  and  its  rocks  and 
minerals,  and  the  sciences  of  physics  and  chemistry  afford 
means  for  the  analysis  of  the  structure  and  composition, 
spectroscopic  characters,  etc.,  which  distinguish  meteorites 
from  other  bodies. 


CHAPTER  II 

PHENOMENA   OF  FALL 

The  fall  of  a  meteorite  is  usually  accompanied,  as  has 
already  been  noted,  by  phenomena  of  light  and  sound. 
These  phenomena  may  be  of  a  startling  and  violent  char- 
acter or  scarcely  perceptible.  Their  nature  and  extent 
obviously  vary  with  the  distance  of  the  observer  from  the 
place  of  passage  of  the  meteor  or  from  its  place  of  fall,  and 
with  the  time  of  fall.  Occasionally  the  passage  of  a  meteor 
producing  meteorites  may  be  observed  over  an  area  of 
thousands  of  square  miles.  Falls  occurring  during  the 
daytime  may  present  no  visible  phenomena  of  light  and 
occasionally  no  sound  may  be  heard,  but  usually  light  or 
sound  is  observed.  Brief  descriptions  of  the  phenomena 
which  have  accompanied  the  fall  of  meteorites  at  different 
periods  and  over  various  parts  of  the  earth's  surface  are 
given  following. 

At  the  fall  of  Tabory,  Perm,  Russia  (Fig.  i),  which  took 
place  at  12:30  p.  M.,  August  30,  1847,  a  fiery  mass  appeared 
in  a  clear  sky  and  moved  in  an  almost  horizontal  direction 
toward  the  northeast.  It  spread  sparks  in  its  way  which 
left  a  bright,  smoky  trace  after  them,  and  some  observers 
saw  an  illuminated  stripe  remaining  after  the  mass  had 
passed.  The  fiery  mass  remained  in  view  only  two  or 
three  seconds.  Two  or  three  minutes  later,  sounds  like  the 
firing  of  many  cannon  were  heard.  In  several  villages  of 
the  region,  black,  warm  stones  weighing  from  two  to  twenty 
pounds  fell  to  the  earth. 

At  the  fall  of  Mocs,  Hungary,  which  occurred  February 
3,  1882,  at  3  145  P.M.,  an  intensely  brilliant  meteor  was  seen 
in  a  cloudless  sky,  then  a  rolling  noise  and  violent  detona- 
tions were  heard.  At  the  spot  where  the  light  was  first 
observed,  a  white,  cirrus-like  cloud  extended  in  the  form  of 
a  white  stripe  from  west  to  east.  About  a  thousand  stones 

7 


8 


METEORITES 


fell   at  this  time,  the  largest  of  which    weighed    70    kilos 
(154  pounds). 

The  fall  which  tocrk  place  at  Sokobanja,  Servia,  about 
2:00  P.M.,  October  13,  1877,  was  introduced  by  two  ex- 
plosions like  salvos  of  artillery,  accompanied  by  a  brilliant 
display  of  light  such  as  attends  the  bursting  of  shells.  A 
dense,  black  smoke  was  observed  at  a  considerable  altitude, 


FIG   j —  pall  Of  the  Tabory,  Russia,  meteorite,  12:30  P.  M.,  August  30,  1847. 

and  this  broke  up  into  three  columns  which  gradually 
changed  to  a  white  smoke.  The  noise  lasted  for  some  time 
and  resembled  the  firing  of  musketry.  Soon  after  the  first 
sound  a  number  of  meteorites  fell  over  an  area  a  mile  and  a 
half  in  length  and  a  half-mile  in  breadth.  The  largest  of 
these  weighed  38  kilos  (84  pounds). 

At  Sauguis,  France,  at  2:30  A.  M.,  September  7,  1868,  a 
meteor  emitting  a  pale  green  light  traversed  the  sky  and 
broke  up,  leaving  a  faint,  whitish  cloud  which  lasted  for 
some  time.  The  disappearance  of  this  cloud  was  succeeded 
by  a  noise  as  of  thunder,  followed  by  three  or  four  loud 


PHENOMENA   OF   FALL  9 

detonations,  which  were  heard  over  a  wide  area.  The 
inhabitants  of  Sauguis  heard  in  addition  to  these  noises  a 
sound  like  that  produced  by  quenching  hot  iron  in  water 
and  a  dull  thud.  A"  stone  weighing  about  4  pounds  was 
found  to  have  fallen  in  the  bed  of  a  small  stream  where  it 
was  broken  to  fragments. 

The  fall  of  Khairpur,  India,  which  took  place  September 
23,  1873,  at  5:00  A.  M.,  was  introduced  by  the  appearance 
of  a  cluster  of  meteors  in  the  west.  Each  member  of  the 
cluster  is  described  as  having  exceeded  in  brightness  a  star 
of  the  first  magnitude  and  the  meteors  left  behind  them  a 
train  from  3°  to  5°  in  breadth.  The  first  thought  of  one 
observer  was  that  he  was  gazing  at  a  rocket,  but  this  opinion 
was  soon  dispelled  as  the  object  rapidly  increased  in  bright- 
ness and  came  toward  him  leaving  a  train  behind.  The 
motion  was  not  rapid  but  steady  and  by  the  time  the  mass 
had  come  to  within  about  10°  of  the  meridian,  which  it 
passed  south  of  the  zenith,  it  assumed  an  exceedingly  bril- 
liant appearance,  the  larger  fragments,  glowing  with  intense 
white  light  with  perhaps  a  shade  of  green,  taking  the  lead  in 
the  cluster,  surrounded  and  followed  by  a  great  number  of 
smaller  ones,  each  drawing  a  train  after  it  which,  blending 
together,  formed  a  broad  belt  of  a  brilliant,  fiery  red  color. 
This  light  illuminated  the  whole  country  like  an  electric 
light.  The  meteor  proceeded  in  this  way  till  it  reached  a 
point  nearly  due  east,  paling  again  as  it  drew  near  the  hori- 
zon and  about  20°  above  the  horizon  appeared  to  go  out. 
The  train  continued  very  bright  for  some  time  and  was 
distinctly  traceable  for  three-quarters  of  an  hour  after.  At 
first  it  changed  to  a  dull  red,  then,  as  the  morning  broke,  to  a 
line  of  silvery  gray  clouds  that  divided  into  several  portions 
and  floated  away  on  the  wind.  After  the  disappearance  of 
the  meteor  and  while  the  train  still  attracted  attention, 
there  was  an  interval  of  perfect  silence,  then  a  loud  report, 
followed  by  a  long  reverberation  that  gradually  died  away 
as  a  roll  of  distant  thunder.  A  number  of  stones  fell  from 
this  meteor,  over  an  area  16  miles  long  by  3  miles  wide. 
The  largest  stone  found  weighed  about  10  pounds. 

The  fall  which  took  place  at  Orvinio,  Italy,  August  31, 


10  METEORITES 

1872,  was  ushered  in  by  the  appearance  of  what  seemed  to 
be  a  large  star  of  a  red  color  traversing  the  sky  in  a  northerly 
direction.  This  increased  in  brilliance  as  it  drew  on  and 
left  a  white  train  in  its  wake.  At  a  certain  point  it  became 
brilliantly  white  and  vanished,  leaving  a  luminous  cloud 
which  continued  to  be  visible  for  a  quarter  of  an  hour. 
After  the  lapse  of  two  or  three  minutes  two  reports  were 
heard,  the  first  like  that  of  a  cannon,  the  second  like  a  series 
of  from  three  to  six  guns  fired  in  rapid  succession.  A  stone 
weighing  about  7  pounds  fell  at  Orvinio  and  some  fragments 
were  thought  to  have  been  carried  further  northward. 

The  fall  at  Hessle,  Sweden,  which  occurred  January  I, 
1869,  at  12:20  P.M.,  was  accompanied  by  a  sound  resembling 
heavy  peals  of  thunder,  followed  by  a  rattling  noise  as  of 
wagons  at  a  gallop  and  ending  with  a  sound  at  first  like  an 
organ  tone  and  later  like  that  of  hissing.  Many  small 
stones  fell  in  this  shower.  One  struck  ice  close  to  where  a 
man  was  fishing  and  rebounded.  He  picked  it  up  and 
found  it  warm. 

Witnesses  of  the  fall  of  the  meteorite  of  Hraschina 
(Agram)  in  Croatia,  May  26,  1751,  state  that  about  6:00 
p.  M.,  as  the  sun  was  going  down,  a  fiery  ball  appeared  in  the 
sky,  which  after  dividing  into  two  parts  with  a  report  like 
the  sound  of  artillery,  scattered  more  so  that  it  appeared 
like  a  fiery  chain  falling  from  heaven.  After  it  trailed  a 
dark  smoke  which  exhibited  different  colors.  Two  iron 
masses,  one  weighing  80  pounds  and  the  other  16  pounds, 
were  found  to  have  fallen  in  a  field.  The  accompanying 
view  (Fig.  2)  drawn  by  Haidinger  from  the  accounts  of 
witnesses  represents  the  large  and  small  masses,  and  A  the 
cloud  from  which  they  came. 

At  Lance,  France,  a  fall  which  occurred  July  23,  1872  at, 
5:20  P.  M.,  was  first  observed  as  a  sudden  increase  of  light 
during  full  sunshine.  A  brilliant  double  meteor  of  a  rose- 
orange  color  was  then  seen  traversing  the  heavens  with 
enormous  velocity  toward  the  northeast.  It  separated  into 
two  luminous  globes,  which  are  said  to  have  had  the  appear- 
ance of  two  candle  flames  proceeding  horizontally.  These 
passed  out  of  sight  at  a  very  low  elevation,  their  disappear- 


PHENOMENA   OF    FALL  11 

ance  being  followed  by  a  sharp  sound  without  echo.  The 
inhabitants  of  villages  to  the  north  saw  a  small  cloud  of 
smoke  and  heard  a  tremendous  explosion  so  severe  that  it 
caused  houses  to  shake.  A  large  stone  weighing  103  pounds 
which  penetrated  the  soil  to  a  depth  of  four  feet  was  found 
at  Lance  and  a  smaller  one  about  six  miles  distant.  The 
trajectory  of  this  meteorite  seems  to  have  been  remarkably 
flat.  Its  velocity  was  calculated  to  have  been  2200  feet 
per  second. 


FIG.  2. —  Fall  of  the  Agram,  Croatia,  meteorite,  about  6:00  P.  M.,  May  26,  1751. 
At  the  left  the  sun  is  represented  as  shining. 

The  meteor  which  preceded  the  fall  which  took  place  at 
Weston,  Connecticut,  at  6:30  A.  M.,  December  26,  1807, 
was  first  seen  as  a  globe  of  fire  about  one-half  the  diameter 
-of  the  moon,  rising  into  the  sky  from  the  north.  The 
progress  of  the  meteor  is  described  as  not  so  rapid  as  that  of 
ordinary  meteors  or  shooting  stars.  As  the  morning  was 
cloudy  the  meteor  passed  in  its  course  behind  the  clouds 
at  intervals.  The  dark  clouds  nearly  obscured  it  but  it 
shone  through  the  thinner  clouds  and  in  the  clear  sky  it 
flashed  with  a  vivid  light  like  that  of  heat  lightning.  In  the 
clear  sky  a  brisk  scintillation  was  also  observed  about  the 
body  of  the  meteor,  like  that  of  a  burning  fire-brand  carried 
against  the  wind.  A  conical  train  of  light  was  also  seen  to 


12  METEORITES 

attend  it,  waving,  and  in  length  about  10  or  12  diameters  of 
the  body.  The  meteor  disappeared  about  15°  short  of  the 
zenith.  It  did  not  vanish  instantaneously  but  grew  fainter 
and  fainter  "as  a  red-hot  cannon  ball  would  do  if  rapidly 
cooled."  The  whole  period  between  the  first  appearance 
and  the  total  extinction  was  estimated  as  about  30  seconds. 
About  30  or  40  seconds  after  this  disappearance,  three  loud 
and  distinct  reports  like  those  of  a  small  cannon  near  at 
hand  were  heard.  Then  followed  a  rapid  succession  of 
duller  reports,  running  into  each  other  and  producing  a 
continued  rumbling  like  that  of  a  cannon  ball  rolling  over  a 
floor  with  a  varying  intensity  of  sound.  Some  observers 
compared  the  sound  to  that  of  a  wagon  running  rapidly 
down  a  long  and  stony  hill,  and  others  to  a  volley  of  musketry 
protracted  into  what  is  called  a  running  fire.  This  sound 
died  away  in  the  direction  from  which  the  meteor  came. 
Stones  fell  from  this  meteor  at  three  different  places  in  the 
line  of  movement  over  an  area  about  10  miles  long.  The 
largest  and  last  to  fall  weighed  about  200  pounds.  Especial 
interest  attaches  to  the  circumstances  of  this  fall  on  account 
of  the  fact  that  the  possibility  of  such  an  occurrence  was 
at  that  time  scarcely  believed  and  the  general  opinion  was 
expressed  by  the  President  of  the  United  States,  Thomas 
Jefferson,  in  the  remark  that  it  was  easier  to  believe  that 
Yankee  professors  would  lie  than  to  believe  that  stones 
would  fall  from  heaven.  Subsequent  evidence  has,  however, 
left  no  doubt  that  the  Yankee  professors  (Profs.  Silliman 
and  Kingsley  of  Yale),  as  well  as  other  historians  of  the 
fall,  were  describing  a  real  occurrence. 

The  meteorite  which  fell  at  Warrenton,  Missouri,  about 
sunrise  January  3,  1877,  first  indicated  its  coming  by  a 
sound  described  by  some  observers  as  like  the  whistle  of  a 
locomotive  and  by  others  as  like  the  passage  of  a  cannon 
ball  through  the  air.  To  four  observers  the  sound  became 
louder  and  louder  and  a  stone  struck  a  tree  near  them, 
breaking  off  the  limbs  and  coming  to  the  ground  with  a 
crash.  The  snow  was  melted  and  the  frozen  ground  thawed 
near  where  the  stone  fell,  but  the  pieces  though  warm  were 
easily  handled.  The  stone  was  broken  by  the  fall  but 


PHENOMENA   OF   FALL  13 

the  fragments  aggregated  nearly  100  pounds  in  weight.  No 
explosion  was  heard  nor  were  any  luminous  phenomena 
noted. 

The  meteoritic  shower  which  occurred  near  New  Concord, 
Ohio,  about  12:30  p.  M.,  May  i,  1860,  was  introduced  by 
a  strange  and  terrible  report  in  the  heavens,  which  shook 
the  houses  for  many  miles  about.  The  first  report  was 
immediately  overhead  and  after  an  interval  of  a  few 
seconds  was  followed  by  similar  reports  with  such  increasing 
rapidity  that  after  reaching  the  number  of  twenty-two  they 
were  no  longer  distinct  but  became  continuous  and  died 
away  like  distant  thunder.  Three  men  working  in  a  field 
heard,  after  the  first  terrible  report,  a  buzzing  noise  over- 
head and  soon  observed  a  large  body  descend  and  strike 
the  earth  at  a  distance  of  about  one  hundred  yards.  This 
body  proved  to  be  a  large  stone  which  buried  itself  about 
two  feet  beneath  the  surface  and  when  obtained  was  quite 
warm.  The  day  was  cool  and  the  sky  covered  at  the  time 
with  light  clouds.  At  Cambridge,  Ohio,  eight  miles  west, 
three  or  four  distinct  explosions  were  heard  like  the  firing 
of  heavy  cannon,  with  an  interval  of  a  second  or  two  be- 
tween each  report.  This  was  followed  by  sounds  like  the 
firing  of  musketry  in  quick  succession  which  ended  with  a 
rumbling  noise  like  distant  thunder. 

The  Cabin  Creek,  Arkansas,  meteorite,  one  of  the  few 
irons  and  the  largest  iron  ever  seen  to  fall,  fell  at  3  :oo  p.  M., 
March  27,  1886.  It  gave  the  first  indication  of  its  approach 
to  the  party  who  was  nearest  it,  a  lady  in  a  house  75  yards 
away,  by  a  very  loud  report  which  caused  "the  dishes  in  the 
closet  to  rattle  and  was  louder  than  thunder."  Running 
out  of  the  house  the  lady  saw  limbs  falling  from  the  top  of  a 
tall  pine  tree,  107  feet  high.  Three  hours  later  a  hole  was 
found  near  the  tree  in  which  an  iron  meteorite  had  buried 
itself  to  the  depth  of  three  feet.  The  ground  was  warm  and 
the  iron  as  hot  as  men  could  well  handle.  The  loud  report 
which  startled  the  first  mentioned  observer  was  heard  as 
far  as  75  miles  away  and  was  there  followed  by  a  hissing 
sound  as  if  metal  had  come  in  contact  with  water.  No 
luminous  phenomena  were  reported. 


14  METEORITES 

The  fall  of  the  iron  meteorite  of  Mazapil,  Mexico,  which 
occurred  about  9  P.  M.,  November  27,  1885,  was  indicated 
to  the  nearest  observer  by  a  loud,  sizzling  noise  as  though 
something  red-hot  was  being  plunged  into  cold  water,  and 
almost  instantly  there  followed  a  somewhat  loud  thud. 
The  air  was  at  once  filled  with  a  phosphorescent  light  with 
small  luminous  sparks  suspended  in  it.  Horses  in  the 
vicinity  were  much  frightened.  The  luminous  air  soon 
disappeared  and  there  remained  on  the  ground  a  light  such 
as  is  made  when  a  match  is  rubbed.  After  the  observers 
had  recovered  from  their  surprise  they  saw  a  hole  in  the 
ground  and  in  it  a  ball  of  light.  They  feared  this  ball  would 
explode  and  retired  for  a  time,  but  returning  found  in  the 
hole  what  looked  like  a  stone  which  was  too  hot  to  handle. 
This  the  next  day  they  found  to  be  an  iron  weighing  about 
10  pounds.  The  hole  was  about  one  foot  deep. 

At  the  fall  of  the  iron  meteorite  of  Braunau,  Bohemia, 
which  took  place  July  14,  1847,  at  3:45  A.  M.,  the  people  of 
Braunau  were  wakened  from  sleep  by  two  violent  sounds 
like  cannon  shots  followed  by  a  whistling  and  rushing  sound 
which  lasted  several  minutes.  Those  who  hastened  into 
the  open  air  saw  to  the  northwest  in  a  sky  in  which  some 
stars  were  yet  visible,  a  small,  black 'cloud.  This  cloud 
glowed  and  emitted  tongues  of  light,  two  of  which  flashed 
to  the  earth.  About  the  fiery  cloud  was  seen  one  of  ash- 
gray  color  which  finally  disappeared  in  the  direction  in  which 
the  wind  was  blowing.  An  iron  meteorite  weighing  48 
pounds  was  found  in  a  hole  three  feet  deep,  and  this  six  hours 
after  the  fall  was  so  hot  as  to  burn  the  hands  of  those  who 
touched  it.  About  a  mile  away  to  the  southeast  a  mass 
weighing  35  pounds  fell  through  the  roof  of  a  house  and  near 
a  bed  where  three  children  were  sleeping. 

At  the  fall  of  the  Rowton,  England,  meteorite,  which  took 
place  at  3:40  P.  M.,  April  20,  1876,  a  strange,  rumbling  noise 
was  heard,  followed  almost  instantaneously  by  a  startling 
explosion  resembling  a  discharge  of  heavy  artillery.  About 
an  hour  later  a  hole  was  found  in  the  ground  and  at  a  depth 
of  1 8  inches  in  this  hole  there  reposed  an  iron  meteorite 
weighing  7^  pounds. 


PHENOMENA   OF    FALL 


15 


At  Quenggouk,  India,  a  meteor  burst  into  view  at  about 
half-past  three  A.  M.,  December  27,  1857.  It  was  in  the 
western  quarter  of  the  sky.  It  sped  across  the  sky  in  an 
almost  due  easterly  direction  seeming  "three  times  as  large 
as  the  full  moon"  and  with  a  blinding  brilliancy  of  light. 
Far  behind  its  brilliant  forward  point  there  trailed  a  great, 


FIG.  3. —  Fall  of  the  Knyahinya,  Hungary,  meteorite,  5.00  p.  M.,  January  9,  1866. 

luminous,  variegated  nebulous  cloud.  A  terrific  explosion 
was  heard,  followed  by  lesser  ones  and  a  protracted  rumbling. 
Three  small  stones  were  found  to  have  struck  the  ground. 

At  the  fall  of  Knyahinya,  Hungary  (Fig.  3),  which,  took 
place  about  5:00  p.  M.,  January  9,  1866,  those  nearest  the 
point  of  fall  heard  sounds  like  cannon-shots  followed  by  a 
noise  like  the  boiling  of  water  and  a  long  roll.  At  the  same 
time  a  cloud  of  smoke  appeared  in  the  sky  from  which  stones 
fell.  These  observers  saw  no  light,  but  those  at  a  distance 


16  METEORITES 

of  10  or  12  miles  saw  a  fire  ball  of  the  color  of  white-hot  iron 
with  edges  of  ultramarine  blue.  Some  saw  this  divide  in 
two.  About  1000  stones,  ranging  in  size  from  2  grams  to 
300  kilograms,  were  precipitated  over  an  area  about  9  miles 
long  by  3  miles  wide.  The  stones  picked  up  immediately 
after  the  fall  were  described  as  being  lukewarm  or  warm. 
The  largest  stone  found  penetrated  the  soil  to  a  depth  of 
II  feet,  entering  in  an  oblique  direction.  From  subsequent 
measurements  it  was  calculated  that  the  meteor  first  ap- 
peared at  a  height  of  7^/4  miles  and  dropped  almost  directly 
downward. 

Phenomena  of  especial  impressiveness  seem  to  have  at- 
tended the  fall  of  Homestead,  Iowa,  which  took  place  Febru- 
ary 12,  1875,  about  10  p.  M.  A  meteor  was  seen  moving 
north  and  east  and  from  the  first  the  light  of  the  meteor  could 
hardly  be  tolerated  by  the  naked  eye  turned  full  upon  it. 
Several  observers  who  were  facing  south  at  the  first  flash, 
.say  that  upon  looking  full  at  the  meteor  it  appeared  to  them 
round,  and  almost  motionless  in  the  air,  and  as  bright  as  the 
sun.  Its  light  was  not  steady,  but  sparkled  and  quivered 
like  the  exaggerated  twinklings  of  a  large  fixed  star,  with 
now  and  then  a  vivid  flash.  To  these  observers,  all  of 
whom  stood  near  the  meteor's  line  of  flight,  its  size  seemed 
gradually  to  increase,  also  its  motion,  until  it  reached  a  point 
almost  overhead,  or  in  a  direction  to  the  east  or  west  of  the 
zenith,  when  it  seemed  to  start  suddenly,  and  dart  away  on 
its  course  with  lightning-like  rapidity.  The  observers  who 
stood  near  to  the  line  of  the  meteor's  flight  were  quite  over- 
come with  fear,  as  it  seemed  to  come  down  upon  them  with 
a  rapid  increase  of  size  and  brilliancy,  many  of  them  wishing 
for  a  place  of  safety  but  not  having  time  to  seek  one.  In 
this  fright  animals  took  part,  horses  shying,  rearing,  and 
plunging  to  get  away,  and  dogs  retreating  and  barking  with 
signs  of  fear.  The  meteor  gave  out. marked  flashes  in  its 
course,  one  more  noticeable  than  the  rest,  when  it  had  com- 
pleted about  two-thirds  of  its  visible  flight.  All  observers 
who  stood  within  twelve  miles  of  the  meteor's  path  say  that 
from  the  time  they  first  saw  it,  to  its  end,  the  meteor  threw 
down  "coals"  and  "sparks." 


PHENOMENA   OF   FALL  17 

Thin  clouds  of  smoke  or  vapor  followed  in  the  track  of 
the  meteor  and  seemed  to  overtake  it  at  times,  and  then 
were  lost.  These  clouds  or  masses  of  smoke  gave  evidence 
of  a  rush  of  air  with  great  velocity  into  the  space  behind  the 
meteoric  mass.  The  vapor  would  seem  to  burst  out  from 
the  body  of  the  meteor  like  puffs  of  steam  from  the  funnel 
of  a  locomotive,  or  smoke  from  a  cannon's  mouth,  and  then 
as  suddenly  be  drawn  into  the  space  behind  it.  The  light 
of  the  meteor's  train  was  principally  white,  edged  with  yel- 
lowish green  throughout  the  greater  part  of  its  length,  but 
near  to  the  body  of  the  meteor  the  light  had  a  strong  red 
tinge.  The  length  of  the  train  was  variously  estimated,  but 
was,  probably,  about  9°,  or  from  seven  to  twelve  miles,  as 
seen  from  Iowa  City.  The  light  about  the  head  of  the 
meteor  at  the  forward  part  of  it,  was  a  bright,  deep  red,  with 
flashes  of  green,  yellow,  and  other  prismatic  colors.  The 
deep  red  blended  with  and  shaded  off  into  the  colors  of  the 
train  at  the  part  following;  but  the  whole  head  was  enclosed 
in  a  pear-shaped  mass  of  vivid  white  light  next  to  the  body 
of  the  meteor,  and  the  red  light  fringed  the  white  light  on 
the  edges  of  the  figure,  and  blended  with  it  on  the  side 
presented  to  the  eye. 

From  three  to  five  minutes  after  the  meteor  had  flashed 
out  of  sight,  observers  near  the  south  end  of  its  path  heard 
an  intensely  loud  and  crashing  explosion  that  seemed  to 
come  from  the  point  in  the  sky  where  they  first  saw  it. 

This  deafening  explosion  was  mingled  with,  and  followed 
by,  a  rushing,  rumbling,  and  crashing  sound  that  seemed  to 
follow  up  the  meteor's  path,  and  at  intervals,  as  it  rolled 
away  northward,  was  varied  by  the  sounds  of  distinct 
explosions,  the  volume  of  which  was  much  greater  than  the 
general  roar  and  rattle  of  the  continuous  sounds.  This 
commotion  of  sounds  grew  fainter  as  it  continued,  until  it 
died  away  in  three  to  five  explosions  much  fainter  than  the 
rest. 

From  one  and  a  half  to  two  minutes  after  the  dazzling, 
terrifying,  and  swiftly  moving  mass  of  light  had  extinguished 
itself  in  five  sharp  flashes,  five  quickly  recurring  reports  were 
heard.  The  volume  of  sound  was  so  great  that  the  rever- 


18  METEORITES 

berations  seemed  to  shake  the  earth  to  its  foundations, 
buildings  quaked  and  rattled,  and  the  furniture  that  they 
contained  jarred  about  as  if  shaken  by  an  earthquake;  in 
fact,  many  believed  that  an  earthquake  was  in  progress. 
Quickly  succeeding,  and  in  fact  blended  with  the  explosions, 
came  hollow  bellowings,  and  rattling  sounds,  mingled  with 
a  clang,  and  clash,  and  roar  that  rolled  slowly  southward  as 
if  a  tornado  of  fearful  power  was  retreating  upon  the  meteor's 
path. 

The  phenomena  observed  in  the  fall  of  a  meteorite  are 
due  chiefly  to  the  resistance  of  the  air,  some  of  the  effects 
of  which  may  be  considered  in  a  general  way  as  follows: 

A  body  in  moving  through  any  medium  such  as  air  or 
water  experiences  a  certain  resistance;  for  the  moving  body 
sets  in  motion  those  parts  of  the  medium  with  which  it  is  in 
contact,  and  thereby  loses  an  equivalent  amount  of  its  own 
motion. 

This  resistance  increases  with  the  surface  of  the  moving 
body;  thus  a  soap-bubble  or  a  snowflake  falls  more  slowly 
than  a  drop  of  water  of  the  same  weight.  It  also  increases 
with  the  density  of  the  medium;  in  rarefied  air  it  is  less  than 
in  air  under  the  ordinary  pressure;  and  in  this  again  it  is 
less  than  in  water. 

The  resistance  also  increases  with  the  velocity  of  the  mov- 
ing body,  and  for  moderate  velocities  is  proportional  to  the 
square;  for,  supposing  the  velocities  of  a  body  made  twice 
as  great,  it  must  displace  twice  as  much  matter,  and  must 
also  impart  to  the  displaced  particles  twice  the  velocity. 
For  high  velocities  the  resistance  in  a  medium  increases 
in  a  more  rapid  ratio  than  that  of  the  square,  for  some  of  the 
medium  is  carried  along  with  the  moving  body,  and  this, 
by  its  friction  against  the  other  portions  of  the  medium, 
causes  a  loss  of  velocity. 

Light  bodies  fall  more  slowly  in  air  than  heavy  ones  of 
the  same  surface,  for  the  moving  force  is  smaller  compared 
with  the  resistance.  The  resistance  to  a  falling  body  may 
ultimately  equal  its  weight;  it  then  moves  uniformly  forward 
with  the  velocity  which  it  has  acquired.  Thus,  a  raindrop 
falling  from  a  height  of  3000  feet  should,  when  near  the 


PHENOMENA   OF   FALL  19 

ground,  have  a  velocity  of  nearly  440  feet  per  second,  or 
that  of  a  musket-shot;  owing,  however,  to  the  resistance  of 
the  air,  its  actual  velocity  is  probably  not  more  than  30 
feet  per  second. 

The  slowing  down  by  the  resistance  of  the  air,  of  a  body 
having  the  velocity  of  a  moving  meteorite,  has  been  cal- 
culated for  a  number  of  special  cases  by  Schiaparelli.  He 
found  that  a  ball  i^  inches  in  diameter  with  a  specific 
gravity  of  3.5  and  having  an  initial  velocity  of  9  miles  per 
second  would  have  its  velocity  reduced  to  ^3  of  a  mile  per 
second  on  arriving  at  the  point  where  the  barometric  pressure 
is  Vee  that  at  the  earth's  surface.  If  the  ball  had  an  initial 
velocity  of  40  miles  per  second  the  reduction  of  velocity  in  the 
early  stages  of  its  fall  would  be  much  greater,  and  on  arriving 
at  the  point  where  the  atmospheric  pressure  is  Vee  that  at  the 
earth's  surface  it  would  be  reduced  nearly  to  that  of  the 
ball  which  started  with  a  velocity  of  9  miles  per  second. 

The  changes  are  shown  in  full  in  the  following  table: 

Initial  velocity  72,000  meters  Initial  velocity   16,000  meters 

(40  miles)  per  second  (9  miles)  per  second 

Remaining                    Atmospheric  Remaining                       Atmospheric 

velocity,                           pressure  velocity,                             pressure 

in  meters                         in  mm.  in  meters                             in  mm. 

72,000 o .  0600  16,000 o .  oooo 

60,000 o .  0005  14,000 o .  0064 

48,000 0.0013  12,000 0.0162 

36,000 0.0031  10,000 0.0322 

24,000 o .  0082  8,000 o .  0620 

1 2,000 o .  03 58  6,000 o.i  280 

8,000 0.0816  4,000 °-3°55 

4,OOO 0.3151  2,OOO 1-2293 

2,000 i .  2489      i  ,000 4 . 2986 

1,000 4.3182       500 11.6192 

500 ii  .6388 

The  same  author  has  calculated  that  for  a  body  to  reach 
the  earth  with  a  velocity  of  500  meters  (^3  mile)  per  second 
it  must,  if  of  the  specific  gravity  of  a  stone  meteorite,  have 
a  diameter  of  2.61  meters  (8  feet),  and  if  an  iron  meteorite, 
1.17  meters  (3  feet). 

Niessl*  has  calculated  for  several  observed  meteoric 
falls  the  height  above  the  earth  at  which  their  initial  velocity 

*Sitzb.  Wien  Akad.,  1884,  89,  2,  283-293. 


20  METEORITES 

was  overcome  and  from  which  they  fell  under  the  influence 
of  the  earth's  gravity  alone.     These  heights  were: 

Homestead 3.7  km. 

Krahenberg 8.2  km. 

Mocs • 8.4  km. 

Weston 1 1 . 1  km. 

Knyahinya.  .  . 11.9  km. 

Braunau 14.8  km. 

Orgueil 23.0  km. 

Pultusk 41 . 5  km. 

Hraschina 46.7  km. 

The  slowing  up  of  a  meteorite  by  the  resistance  of  the  air 
exerts  a  powerful  disruptive  force  upon  it,  since  the  rear  of 
the  meteorite  tends  to  travel  with  a  planetary  velocity  while 
the  forward  part  is  being  checked.  Thus  Hauser  calculated 
that  a  meteorite  having  a  volume  of  a  cubic  meter  and  being 
a  square  meter  in  section  would,  if  moving  at  a  velocity  of 
30  miles  per  second,  develop  an  internal  disruptive  force  of 
nearly  3  billion  kilogram-meters  on  arriving  within  16  miles 
of  the  earth's  surface.  That  this  force  would  tend  to  burst 
the  meteorite  there  can  be  no  doubt. 

The  enormous  heat  developed  by  such  a  checkingof  velocity 
or  the  conversion  of  its  motion  into  heat,  should  also  be  con- 
sidered. Thus  a  body  weighing  one  pound,  and  moving  25 
miles  a  second,  has  momentum  sufficient  to  raise  (25  x  528o)2 
-i-2g  =  27 1, 500,000  pounds  one  foot.  By  Joule's  equivalent, 
the  raising  of  772  pounds  one  foot  corresponds  to  the  heat 
necessary  to  raise  one  pound  of  water  one  degree  Fahren- 
heit. If  the  capacity  of  the  meteoric  substance  for  heat  is 
0.2  (that  of  iron  is  0.12),  the  loss  of  a  velocity  of  25  miles 
would  be  equivalent  to  heating  (27 1,500,000 -5-0.2)^-77 2  = 
1,760,000  pounds  of  the  substance  one  degree  Fahrenheit, 
if  the  whole  of  the  motion  was  transformed  into  heat. 

The  sounds  like  thunder  usually  accompanying  the  fall 
of  a  meteorite,  are  doubtless  due,  as  in  the  case  of  lightning, 
to  the  explosive  shock  given  to  the  surrounding  air  by  the 
sudden  heating  of  the  air  in  the  vicinity  of  the  passing 
meteorite.  The  pressure  thus  produced  is,  according  to 
Thomson*  in  the  case  of  lightning,  equal  to  ten  atmospheres 

*  Science,  Dec.  17,  1909. 


PHENOMENA   OF   FALL  21 

and  is  probably  not  less  in  the  fall  of  the  average  meteorite. 
The  prolonged  and  varying  rolling  sound  is  also  due  as  in 
the  case  of  lightning  to  irregular  movements  of  the  meteorite 
in  its  course  through  the  air.  The  first  sound  heard  comes 
from  the  part  of  the  path  nearest  the  observer  and  then 
follows  that  derived  back  along  the  meteor's  path.  Any 
twistings  and  bendings  of  the  course  of  the  meteorite  will 
cause  blendings  and  separations  of  the  sound  waves  which 
will  give  varying  effects. 

The  effect  of  the  impact  of  a  meteorite  upon  the  earth 
depends  among  other  factors  upon  the  velocity  of  the  mete- 
orite and  the  nature  of  the  surface  upon  which  it  falls.  So 
far  as  the  velocity  of  the  meteorite  is  concerned,  all  evi- 
dence indicates,  as  already  noted,  that  the  meteorite  loses 
its  planetary  speed  in  the  upper  layers  of  the  atmosphere 
and  falls  during  the  latter  part  of  its  course  like  any  free 
falling  body. 

Thus  the  velocity  of  the  Middlesbrough  meteorite  on 
striking  the  ground  was  calculated  by  Herschel  to  have 
been  412  feet  a  second.  Borgstrom  reckoned  the  velocity 
of  the  Hvittis  meteorite  from  the  depth  of  the  hole  which  it 
made  in  a  stiff  loam  to  have  been  584  feet  a  second;  that  of 
the  St.  Michel  meteorite  (Fig.  4)  from  similar  observations 
to  have  been  between  563  and  710  feet  a  second,  and  that 
of  the  Shelburne  meteorite  to  have  been  515  feet  per  second. 
The  depth  to  which  a  meteorite  will  penetrate  obviously  de- 
pends much  upon  the  nature  of  the  soil.  A  meteorite  strik- 
ing upon  a  ledge  of  rock  as  did  that  of  Long  Island,  will,  if  it 
is  a  stone  meteorite,  itself  be  shattered.  On  the  other  hand, 
when  striking  soil  meteorites  may  enter  it  to  a  considerable 
depth.  The  Hvittis  and  St.  Michel  meteorites  above  men- 
tioned passed  the  one  into  stiff  clay  and  the  other  into  mo- 
rainic  material  to  a  depth  of  about  two  feet  each.  The 
largest  stone  of  the  Estherville  shower,  weighing  437  pounds, 
penetrated  stiff  clay  to  a  depth  of  eight  feet,  and  the  next 
smaller  stone,  weighing  170  pounds,  embedded  itself  in  sim- 
ilar material  to  a  depth  of  five  feet.  These  were,  however, 
stones  of  higher  specific  gravity  than  those  previously  men- 
tioned. The  Farmington  meteorite  weighing  180  pounds 


22  METEORITES 

went  into  hard  clay  to  a  depth  of  four  feet.     The  Kilbourn 
meteorite,  a  stone  about  the  size  and  shape  of  a  man's  fist, 


FIG.  4. —  Hole  in  ground  made  by  fall  of  the  St.  Michel  meteorite. 
After  Borgstrom. 

passed  in  succession  through  a  barn  roof  composed  of  three 
thicknesses  of  shingles,  a  hemlock  board  an  inch  thick,  and 
another  hemlock  board  of  the  same  thickness  about  four 


PHENOMENA   OF   FALL  23 

feet  below  this.  The  direction  of  penetration  of  a  meteorite 
is  not  always  vertical,  since  the  direction  of  motion  of  the 
meteorite  is  sometimes  tangential.  Thus  the  largest  stone 
of  the  Knyahinya  fall,  a  stone  which  weighed  660  pounds, 
reached  a  depth  in  the  earth  of  eleven  feet,  but  in  a  direc- 
tion inclined  about  27°  from  the  vertical  so  that  a  stake 
driven  down  in  the  center  of  the  hole  which  it  made  failed 
to  strike  it.  Motion  in  a  direction  much  inclined  from  the 
vertical  may  account  for  the  apparent  lack  of  forceful  im- 
pact observed  in  the  fall  of  many  large  iron  meteorites. 
These  masses  with  their  weight  of  many  tons  should  seem- 
ingly reach  to  great  depths  on  striking  the  earth,  but  little 
evidence  of  such  penetration  has  yet  been  secured.  As  a 
rule  these  masses  are  found  near  the  surface. 

The  most  extensive  terrestrial  effect  which  has  ever  been 
ascribed  as  possibly  due  to  meteoritic  impact  is  to  be  seen 
at  Canyon  Diablo,  Arizona,  at  the  point  of  fall  of  the 
Canyon  Diablo  meteorites.  The  immediate  locality  of  the 
fall  is  known  as  Coon  Butte  or  Meteor  Crater.  Here  a 
circular  depression  about  4000  feet  in  diameter  and  570  feet 
deep  occurs  in  the  surface  of  an  otherwise  comparatively 
level  plain.  (Fig.  5).  The  walls  of  this  "crater,"  as  it  has 
been  called,  are  composed  of  limestone  and  sandstone  and 
the  layers  of  these  rocks  dip  away  from  the  center  of  the 
crater  at  varying  angles.  Along  the  southern  wall  the  lime- 
stone and  sandstone  have  been  lifted  vertically  more  than 
100  feet.  At  its  highest  point  the  crater  rim  is  160  feet 
above  the  outlying  plain,  and  at  its  lowest  120  feet.  The 
mass  of  the  crater  rim  is  composed  of  loose,  unconsolidated 
material  varying  in  size  from  microscopic  dust  to  blocks 
weighing  hundreds  of  tons.  The  floor  of  the  crater  is  com- 
paratively level  but  has  probably  been  built  up  by  inwash 
from  the  sides.  Special  significance  is  attached  by  investi- 
gators of  the  region  to  the  presence  of  a  gray  or  white  sand- 
stone, much  of  it  in  the  form  of  a  rock  flour  which  is  found 
in  the  floor  of  the  crater  and  about  its  rim.  This  sandstone 
is  regarded,  on  account  of  its  structure,  as  showing  signs  of 
metamorphism  by  heat.  Mixed  with  this  material  are  part- 
icles of  nickel-iron.  At  a  depth  of  820  feet  below  the  floor 


24 


METEORITES 


METEOR  CRATER-  COCON1NO  COUNTY-  ARIZONA 


VIEW  OF   GRAT£P.   FHC  'oTAr.GE  OF  SEVERAL  MILEi. 


FIG.  5. —  Meteor  Crater,  Arizona.     It  is  about  this  area  that  the  Canyon  Diablo 
meteorites  are  found. 


PHENOMENA   OF   FALL  25 

of  the  crater  undisturbed  strata  of  red  and  yellow  sandstone 
are  found.  Scattered  about  over  the  floor  of  the  plain  iron 
meteorites  have  been  found  in  numbers  reaching  thousands, 
and  in  weight  aggregating  several  tons.  Within  the  crater 
itself  only  a  few  small  meteorites  have  been  found.  The 
peculiar  topographic  form  and  the  associated  meteorites 
lend  considerable  plausibility  -to  a  hypothesis  which  has 
been  urged  by  several  observers  but  especially  by  D.  M. 
Barringer.*  This  hypothesis  ascribes  the  formation  of  the 
crater  to  the  impact  of  a  huge  meteorite  which  was  wholly 
or  in  part  metallic.  The  dimensions  of  this  meteorite  were 
calculated  by  Barringer  and  Tilghman  from  the  size  of  the 
crater  to  have  been  about  500  feet  in  diameter. 

Complete  proof  of  the  correctness  of  the  hypothesis  would 
be  obtained  by  rinding  within  the  crater  above  the  un- 
disturbed sandstone  a  meteoric  mass  or  many  of  them  which 
would  together  approximate  the  size  mentioned.  Although 
a  number  of  borings  have  been  made  in  search  of  such  a 
mass  or  masses,  none  has  as  yet  been  found.  Search  fo.r 
such  a  mass  with  magnetic  instruments  has  likewise  given 
negative  results.  It  has  been  suggested  that  the  enormous 
force  of  impact  might  have  rent  the  mass  of  the  impinging 
body  into  minute  fragments,  some  of  which  are  represented 
by  the  nickeliferous  particles  found  in  the  white  sand,  and 
hence  no  large  mass  now  exists.  No  certain  conclusion  can 
as  yet  be  drawn  in  regard  to  this  view.  An  alternative  to 
the  hypothesis  of  meteoritic  origin  is  to  assume  that  the 
crater  originated  from  some  terrestrial  force,  and  that  the 
occurrence  of  such  meteorites  as  have  been  found  here  is 
purely  coincidental.  This  was  the  conclusion  of  G.  K.  Gil- 
bert, who  ascribed  the  formation  of  the  crater  to  a  steam 
explosion  of  volcanic  origin.  The  opponents  of  this  view, 
however,  state  that  there  are  no  known  volcanoes  or  hot 
springs  near  the  region  to  afford  the  heat  necessary  for  such 
an  action.  It  seems  as  yet  therefore  impossible  to  give  final 
decision  as  to  the  origin  of  the  "crater." 

The  resemblance  of  this  topographic  feature  to  that  of 
the  so-called  volcanoes  of  the  moon  has  often  been  re- 

*Meteor  Crater:  Philadelphia   1909.     Published  by  the  author. 


26 


METEORITES 


FIG.  6. —  Craters  of  the  moon.     They  resemble  Meteor  Crater,  Arizona,  in  form 
and  by  some  have  been  thought  to  be  formed  by  the  impact  of  meteorites. 


PHENOMENA   OF   FALL  27 

marked  and  it  has  been  suggested  that  the  moon  craters  are 
in  reality  impact  pits  caused  by  the  striking  of  large  mete- 
orites upon  the  moon's  surface  (Fig.  6).  Those  who  urge 
this  view  find  cause  for  the  greater  effect  of  such  impact 
upon  the  moon  as  compared  with  the  earth  in  the  absence 
of  an  atmosphere  from  the  moon.  There  is  thus  nothing 
upon  the  moon  to  burn  up  falling  bodies  before  they  reach 
its  surface.  There  can  be  no  doubt  that  the  earth's  atmos- 
phere affords  an  immense  protection  to  its  inhabitants  in 
burning  up  bodies  which  would  otherwise  reach  the  earth's 
surface  but  that  meteorites  sufficiently  large  to  make  the 
great  craters  on  the  moon's  surface  have  ever  fallen  on  that 
body  seems  somewhat  questionable. 

Meteorites  show  little  warmth  when  they  arrive  upon  the 
earth.  The  stone  meteorites  at  any  rate  are  almost  always 
spoken  of  as  being  "  milk  warm  "  or  "  barely  warm  "  by  those 
who  pick  them  up  immediately  after  their  fall  to  the  earth. 
Neither  are  there  any  indications  of  any  heating  effect  where 
meteorites  have  struck  the  earth.  No  baking  of  the  soil  or 
charring  of  vegetation  can  be  observed.  Meteorites  have 
also  fallen  in  haystacks,  within  barns  or  in  other  places 
where  a  little  heat  might  start  a  fire  but  have  never  pro- 
duced any  incendiary  effects  so  far  as  known.  This  lack 
of  heat  is  contrary  to  the  general  belief,  the  common  opin- 
ion being  that  meteorites  are  intensely  hot  when  they  reach 
the  earth.  This  opinion  is  evidently  based  on  the  brilliant 
light  emitted  by  meteors  in  their  course  in  the  atmosphere. 
A  little  consideration  of  the  matter,  however,  will  convince 
one  that  no  heating  phenomena  should  be  expected  for  three 
reasons: 

1.  The  substance  of  stone  meteorites  is  a  poor  conductor 
of  heat. 

2.  The  period  in  which  they  might  acquire  heat  is  ex- 
tremely short,  but  a  few  seconds  at  most. 

3.  Any   portion   of  their  surface   sufficiently   heated   to 
become  in  a  condition  even  approaching  viscosity  is  imme- 
diately removed  by  the  pressure  of  the  surrounding  air. 
With  the  iron  meteorites  the  case  is  somewhat  different 
since  they  are  much  better  conductors  of  heat  than  stone 


28 


METEORITES 


meteorites.  They,  therefore,  generally  possess  considerable 
warmth  when  picked  up  immediately  after  their  fall.  The 
Cabin  Creek  meteorite  is  described  as  being  "as  warm  as 
could  be  handled"  after  being  dug  from  a  hole  three  feet 
deep.  The  Mazapil  meteorite  was  so  warm  that  it  could 
be  "barely  handled"  on  removal.  The  heat  emitted  even 
in  these  cases,  however,  was  not  great.  Any  accounts, 
therefore,  of  intense  heat  being  displayed  by  meteorites  can 
usually  be  assumed  to  be  false,  the  observer's  previously 

formed  opinion  probably 
coloring  his  testimony  if  his 
testimony  is  sincere. 

No  meteorite  fall  has  ever 
positively  been  known  to 
have  been  destructive  to 
human  life.  Accounts  pur^ 
porting  to  describe  such 
catastrophes  prove  on  in- 
vestigation to  have  come 
either  from  times  or  countries 
so  remote  that  they  cannot 
be  verified.  Many  accounts 
of  such  an  occurrence  come 
to  us  from  earlier  times,  and 

the  scene  here  pictured  (Fig.  7)  probably  illustrates  destruc- 
tion believed  by  the  early  artist  to  have  been  caused  by 
meteoric  stones  falling  from  the  skies.  But  no  well 
authenticated  occurrence  of  the  sort  is  known.  Perhaps 
the  most  narrow  escape  which  has  ever  been  experienced 
was  that  of  three  children  in  Braunau  at  the  time  of  fall 
of  that  meteorite  in  1847.  This  meteorite,  an  iron 
weighing  nearly  40  pounds,  fell  in  a  room  where  these 
children  were  sleeping  and  covered  them  with  debris,  but 
they  suffered  no  serious  injury.  Other  meteorites  have 
fallen  near  human  beings  but  never  have  struck  them  so  far 
as  credible  information  goes.  That  personal-  injury  or 
death  might  be  caused  by  the  fall  of  a  meteorite  is  entirely 
possible,  in  fact  is  likely  to  occur  at  some  time.  It  is  re- 
markable that  some  falls,  such  for  instance  as  the  showers 


FIG.  7. — Old  drawing  perhaps  repre- 
senting a  fall  of  meteorites. 


PHENOMENA   OF   FALL  29 

in  Iowa  which  occurred  in  fairly  thickly  settled  communities, 
should  not  have  caused  serious  injury  to  the  inhabitants. 

Injury  to  animals  from  falling  stones  has  perhaps  occurred 
in  a  few  instances.  Cattle  were  said  to  have  been  struck 
by  falling  stones  in  the  shower  of  Macao,  Brazil,  in  1836, 
and  a  dog  was  reported  to  have  been  killed  by  a  meteoric 
stone  in  Nakhla,  Egypt,  in  1911.  The  evidence  in  regard 
to  these  occurrences  is  not,  however,  altogether  satisfactory. 
Buildings  have  several  times  been  struck  by  meteorites  and 
usually  have  been  penetrated  by  them.  Besides  the  build- 
ing mentioned  above  as  struck  by  the  Braunau  meteorite, 
a  12-pound  individual  of  the  Pillistfer  fall  fell  through  a  tile 
roof  and  a  floor  of  a  building,  and  the  Kilbourn  meteorite 
penetrated  a  barn.  Buildings  were  also  penetrated  by  the 
Aussun,  Barbotan,  Benares,  and  Massing  meteorites. 

The  following  recommendations  to  observers  on  occasions 
of  the  falls  of  meteorites,  describing  the  points  of  information 
most  desirable  to  be  recorded  regarding  their  characters 
and  appearance,  were  published  by  a  committee  of  the 
British  Association  in  1878:* 

"In  recording  observations  on  the  passage  of  a  meteor 
across  the  sky,  the  points  which  it  is  most  desirable  to  arrive 
at  are:  such  data  as  will  allow  of  our  definitely  noting  the 
direction  of  its  path  and  its  point  of  extinction,  the  duration 
of  the  luminous  phenomenon,  and  of  individual  phases  of 
it,  the  apparent  magnitude  of  the  meteor,  the  luminosity 
as  compared  with  other  brilliant  objects  and  the  changes 
which  it  may  itself  exhibit  in  this  respect  during  the  transit, 
the  duration  of  the  train  (or  i streak'),  and  the  changes  it 
may  undergo  before  extinction  (whether  it  fade  away  simul- 
taneously along  the  entire  length,  or  break  up  into  a  chain 
of  luminous  fragments);  also,  in  cases  where  the  streak  is 
one  of  great  persistence,  the  manner  of  its  final  disappear- 
ance; again,  when  the  meteor  has  been  observed  near  the 
time  of  sunrise,  or  sunset,  what  change  it  wrought  in  the 
appearance  of  the  visible  train  by  the  increasing  or  waning 
light  of  the  sky.  The  sound  attending  its  passage,  if  any, 
and  the  character  of  the  sound,  as  regards  intensity  and  dura- 

*  Rept.  Brit.  Assn.  Adv.  Sci.,  1878,  pp.  375-377. 


30  METEORITES 

tion,  whether  single  and  well  defined,  or  a  series  of  minor 
explosions  closely  following  one  another  should  be  noted 
and  finally,  the  time  of  appearance,  and  that  of  the  inter- 
val before  the  explosion  is  heard. 

"While  it  is  hardly  possible  for  one  observer  to  record 
all  the  data  referred  to,  he  should  not  fail  to  note  such  of 
them  as  may  have  come  clearly  within  his  observation. 
Other  spectators  may  have  remarked  what  he  may  have 
missed,  and  their  joint  observations  may  enable  us  to  arrive 
at  a  complete  physical  history  of  the  meteor  in  question. 

"It  is  desirable  to  determine  two  points  of  the  track  of 
the  meteor,  as  far  asunder  as  possible  —  the  points  of 
appearance  and  extinction  are  to  be  preferred  —  and  to 
indicate  the  former  by  reference  to  some  star  or  constellation 
which  it  overlies,  and  the  latter  by  some  object  on  the  hori- 
zon against  which  it  is  projected.  In  cases  where  the 
meteor  is  seen  in  daytime,  the  data  to  be  arrived  at  are  the 
points  of  appearance  and  its  angular  altitude.  The  former 
may  be  estimated  by  noticing  what  conspicuous  object  lies 
vertically  below  it  on  the  horizon;  a  village  or  a  mountain 
peak.  The  more  distant  the  object  is  from  the  spectator, 
the  more  accurate  will  be  the  determination  of  this  element 
of  the  observation.  If  objects  to  which  reference  can  be 
made  should  be  wanting,  the  direction  may  be  temporarily 
noted,  and  subsequently  determined  by  the  aid  of  a  compass- 
needle.  To  learn  an  angular  altitude  we  dare  not  trust 
general  conclusions,  however  carefully  arrived  at;  even 
experienced  observers  may  be  misled  in  such  cases.  If  a 
vertical  object,  say  the  roof  of  a  house,  or  the  top  of  a  tree, 
happens  to  lie  in  the  direction  under  consideration,  the 
observer  should  approach  it  till  the  line  of  sight  of  the  origin 
of  the  course  of  the  meteor  skirts  the  summit  of  the  ter- 
restrial object.  The  observer  has  now  to  determine  how 
far  he  is  removed  from  the  object  selected,  its  vertical 
height  above  the  plain  on  which  both  are  situated,  and  the 
distance  above  the  ground  of  his  own  eye,  in  order  to  be  in 
a  position  to  determine  the  angular  elevation  of  the  point 
of  appearance  of  the  meteor,  the  position  of  which  he  desires 
to  ascertain. 


PHENOMENA   OF    FALL  31 

;'The  apparent  path  of  the  meteor  is  often  represented  by 
a  line  like  a  bow;  in  other  words,  the  meteor  apparently 
ascends,  culminates,  and  then  takes  a  downward  course. 
This  motion  is,  however,  for  the  most  part  apparent  only; 
and  is  a  consequence  of  the  varying  inclination  which  a 
straight  line  appears  to  form  with  the  horizon  at  different 
points  along  its  course.  The  observer  should  endeavor  to 
determine  as  accurately  as  possible  the  apparent  inclination 
at  those  points  of  the  meteor's  arc,  or  line  of  flight,  which  can 
be  most  readily  identified,  such  as  the  beginning  and  the 
end  of  the  track,  or  those  where  a  break  in  the  luminous 
train  occurs,  as  well  as  that  portion  which  lies  parallel  to 
the  horizon.  The  point  of  extinction  should  especially  be 
noted,  and  this  is  the  more  readily  accomplished  from  the 
fact  that  the  attention  has  been  steadily  directed  to  observ- 
ing the  luminous  phenomena  preceding  it.  In  regard  to 
the  point  of  appearance,  it  is  of  importance  to  determine 
whether  the  impression  made  on  the  observer  was  that  he 
had  witnessed  the  blazing  forth  of  the  meteor  in  the  sky, 
or  whether  the  meteor  had  entered  his  field  of  vision, 
and  a  portion  of  its  luminous  track  had  not  been  seen 
by  him. 

"It  is,  moreover,  of  importance  to  arrive  at  a  knowledge 
of  the  length  of  time  occupied  by  the  meteor  in  traversing 
the  sky;  this  may  sometimes  be  learned  by  counting  the 
ticks  of  a  watch,  or  by  advancing  in  the  direction  of  the 
object  at  a  uniform  rate,  and  counting  the  paces  taken 
during  the  observation.  It  should  also  be  noted  whether 
the  meteor  moves  onward  with  an  accelerating  or  diminish- 
ing velocity. 

"The  brilliancy  of  a  meteor  larger  than  the  fixed  stars  of 
different  magnitudes  can  most  conveniently  be  compared 
with  the  light  of  Venus  or  Jupiter;  and  in  the  case  of  the 
largest  meteors,  with  the  apparent  brilliancy  and  magnitude 
of  the  moon  in  her  several  phases.  The  colour  exhibited 
by  the  meteor  should  also  be  carefully  observed,  and  any 
change  of  hue  along  any  part  of  the  path  should  be  recorded. 
The  luminous  train  left  after  the  disappearance  of  the 
meteor  is  sometimes  very  persistent,  and  often  terminates  in 


32  METEORITES 

a  cloud,  faintly  visible.  Any  peculiar  structure  exhibited 
by  the  train,  or  cloud,  should  be  sketched  on  paper. 

"The  sound  attending  the  flight  of  the  meteor  usually 
consists  either  of  several  distinct  explosions,  or  a  crackling, 
rolling  detonation.  The  closest  attention  should  be  given 
after  the  extinction  of  the  meteor,  for  the  arrival  of  the 
sound  and  the  length  of  the  interval  should  be  carefully 
noted  with  the  watch. 

"Of  the  many  points  which,  as  has  been  shown,  it  is  de- 
sirable that  a  record  should  be  made,  an  individual  observer 


7 

\ 

/ 

*\ 

\            ' 

V 

/ 

\ 

\        / 

,''  ^* 

* 

I^EH         5  ^  —  ^  °' 

Atmosphere 


Earth 

FIG.  8. —  Diagram  showing  effect  of  position  of  observer  on  the  appar- 
ent paths  of  meteors.  The  actual  paths  are  AB,  but  the  apparent 
paths  as  seen  at  O  are  AC.  After  Moulton. 

can  obviously  determine  but  a  few;  all  those  of  them,  how- 
ever, to  the  accuracy  of  which  he  can  certify,  are  of  value 
since  other  observers  may  supply  the  missing  data,  and  the 
whole  may  be  collected. 

"If  a  meteorite  has  fallen,  visit  the  spot  where  it  struck 
the  ground,  and  examine  the  hole  which  it  formed.  Deter- 
mine the  depth,  and  especially  notice  the  direction  of  the 
cavity  in  respect  to  the  points  of  the  compass.  Ascertain 
whether  the  meteorite  was  removed  from  the  ground  soon 
after  its  descent,  and  whether  any  observations  had  been 
made  at  the  time  respecting  its  temperature.  Make  a 
note  of  the  material  forming  the  surface  layer,  and  state 
whether  it  was  moist  or  dry.  Further  inquiries  in  the 
neighborhood  may  lead  to  the  discovery  of  other  meteorites 
which  had  fallen  at  the  same  time,  and  at  points  not  un- 
frequently  miles  distant.  They  may  vary  greatly  in  size; 
and  stones  as  small  as  a  pea  or  bean  may  be  sought  for." 


PHENOMENA   OF   FALL  33 

To  these  suggestions  may  be  added  in  the  case  of  a 
meteoritic  shower  the  recommendation  that  the  distribution 
of  the  meteorites  with  respect  to  their  size  should  be  ob- 
served and  the  extent  and  dimensions  of  the  area  over  which 
they  have  fallen  should  be  determined  as  far  as  possible. 
Also  an  effective  means  of  measuring  the  height  of  a  meteor 
has  been  suggested  by  Sir  Robert  Ball.  This  method  re- 
quires that  two  observers  situated  a  number  of  miles  apart 
should  note  the  meteor  and  its  direction  from  them.  .  Then 
on  a  map  of  any  convenient  scale  a  straight  wire  should  be 
raised  from  the  position  of  each  observer  in  the  direction  in 
which  he  saw  the  meteor.  The  point  of  intersection  of  the 
wires  will  show  the  true  position  of  the  meteor  and  a  per- 
pendicular let  fall  from  this  point  will  show  its  height  ex- 
pressed in  the  scale  of  the  map. 

Further,  the  effect  of  the  position  of  the  observer  on  the 
apparent  paths  of  meteors  should  be  considered.  Thus  in 
the  accompanying  figure  (Fig.  8),  there  are  represented  the 
paths  of  three  meteors  which  are  parallel,  AB,  but  their 
apparent  paths  as  seen  by  an  observer  at  O  will  vary  in  di- 
rection, being  the  lines  AC.  It  is  by  continuing  the  lines 
backward  on  the  celestial  sphere  that  the  point  from  which 
the  meteors  came  can  be  determined. 


CHAPTER  III 

GEOGRAPHICAL  DISTRIBUTION    OF  METEORITES 

Broadly  speaking,  we  know  no  fundamental  reason  why 
meteorites  should  be  any  more  numerous  upon  one  part  of 
the  earth's  surface  than  upon  another. 

Compared  with  the  vast  area  of  space  in  which  meteorites 
wander,  our  earth  is  but  a  point,  and  moreover  a  rotating 
and  wabbling  point,  ever  presenting  new  surfaces  to  the 
portions  of  space  in  which  it  is  traveling.  The  marksman 
who  displays  his  skill  by  shooting  glass  balls  thrown  into 
the  air  would  have  the  difficulty  of  his  task  enormously 
increased  if  he  should  endeavor  to  strike  successively  the 
same  point  upon  the  ball,  especially  if  it  had  in  addition  to 
its  forward  motion  one  of  rapid  rotation  about  a  wabbling 
axis.  Yet  this  is  what  a  falling  meteorite  must  do  if  it  is  to 
reach  any  particular  point  on  the  earth's  surface.  These 
considerations  make  it  difficult  to  believe  that  any  par- 
ticular portion  of  the  earth's  surface  is  more  likely  than 
another  to  receive  meteorite  falls.  However,  knowledge 
of  falls  requires  observers  or  finders  and  they  must  be 
persons  of  sufficient  intelligence  to  recognize  the  nature  of 
their  finds.  Hence  a  map  of  the  localities  from  which 
meteorites  are  known  shows  by  far  .the  larger  part  of  them 
in  civilized  countries  and  the  falls  apparently  the  more  abun- 
dant the  greater  the  population.  Of  634  known  meteorites, 
256  have  been  found  in  Europe  and  177  in  the  United  States. 
Thus  more  than  two-thirds  of  the  known  number  are  from 
less  than  one-eighth  of  the  land  surface.  We  have  no  reason 
to  suppose  that  these  regions  actually  receive  more  mete- 
orites than  others  less  intelligently  populated  and  any  ap- 
parent excess  or  lack  of  meteorites  in  any  given  locality 
must  be  considered  in  the  light  of  these  facts.  Taking 
these  facts  into  consideration,  however,  there  seem  to  be 
certain  inequalities  of  distribution  of  meteorites  which  may 

34 


GEOGRAPHICAL   DISTRIBUTION   OF   METEORITES  35 

be  of  some  significance.  Meteorites  seem  to  be  somewhat 
more  abundant  in  mountainous  or  elevated  regions  than  in 
those  of  an  opposite  character.  Thus  they  seem  to  be  more 
abundant  near  the  Himalayas  in  India,  near  the  Alps  in 
Europe,  and  about  the  high  peaks  of  the  southern  Appala- 
chians in  the  United  States.  The  largest  iron  meteorites 
of  North  America  are  nearly  all  found  in  the  Cordilleras. 
Whether  such  regions  exert  a  greater  gravitational  force  or 
whether  they  present  an  actual  physical  obstacle  to  the  pas- 
sageof  a  meteoriteis  uncertain,  but  it  is  probable  that  if  either 
agency  is  operative  it  is  the  obstructive  one.  Another  seem- 
ing difference  in  distribution  may  be  noted  if  the  meteorites 
of  the  two  hemispheres  of  the  world  be  compared:  Thus  of 
256  meteorites  known  from  the  western  hemisphere,  182  are 
irons  and  only  74  stones;  while  from  the  eastern  hemisphere, 
of  378  known,  299  are  stones  and  only  79  are  irons.  Ber- 
werth  has  sought  to  account  for  the  excess  of  irons  in  the 
New  World  by  the  suggestion  that  the  dry  air  of  the  desert 
areas  which  abound  in  this  hemisphere  has  preserved  mete- 
orites fallen  in  long  distant  periods  while  those  of  a  similar 
age  in  the  other  hemisphere  have  been  exposed  to  a  moist 
climate  and  have  for  the  most  part  been  decomposed.  It 
is  true  that  many  of  the  iron  meteorites  known  from  the 
western  hemisphere  occur  upon  the  Mexican  and  Chilean 
deserts,  but  quite  as  many  come  from  the  southern  Appa- 
lachians, where  a  comparatively  moist  climate  prevails. 
There  are  also  numerous  desert  areas  in  the  Old  World  per- 
haps as  fully  explored  as  those  of  the  New,  so  that  on  the 
whole  the  above  explanation  seems  inadequate. 

Other  remarkable  groupings  of  meteorites  with  regard 
to  their  geographical  distribution  may  be  noted  when  areas 
smaller  than  hemispheres  are  compared.  Thus  of  a  total 
of  nine  meteorites  belonging  to  the  class  of  howardites,  five 
have  fallen  in  Russia.  Of  the  nine  meteorites  known  be- 
longing to  the  class  of  carbonaceous  meteorites,  three  have 
fallen  in  France  and  two  in  Russia. 

Again  small  areas  of  equal  extent  and  equally  well  popu- 
lated vary  curiously  in  their  number  of  meteorite  falls. 
Within  the  state  of  Illinois,  for  instance,  no  meteorite  is 


36  METEORITES  . 

known  ever  to  have  fallen,  while  in  the  state  of  Iowa,  which 
has  about  the  same  area,  but  a  smaller  population,  four 
falls  have  been  noted,  and  from  the  state  of  Kansas,  which 
has  a  larger  area  than  Illinois,  but  a  smaller  and  less  uni- 
formly distributed  population,  twelve  meteorites  are  known. 


CHAPTER  IV 

TIMES   OF  FALL 

Considering  meteorite  falls  by  years  it  should  be  remem- 
bered that  previous  to  the  nineteenth  century  little  reliable 
record  of  such  falls  is  available.  Single  falls  are  known  for 
the  years  1492,  1668,'  1715,  1723,  1751,  1766,  1773,  1785, 
1787,  1790,  1794,  1795,  and  1796,  and  two  falls  each  for  the 
years  1753,  1768,  and  1798.  Moreover,  for  the  early  part 
of  the  nineteenth  century  the  record  is  not  very  complete, 
since  during  that  period  the  possibility  of  meteorite  falls 
was  yet  much  doubted.  But  from  1800  to  1910,  331  falls 
may  be  accepted  as  well  authenticated  as  to  their  month 
and  year.  During  this  period  eleven  years  show  no  falls 
whatever.  These  years  are,  1800,  1801,  1809,  1816,  1817 
1832,  1839,  1888,  1906,  1908,  and  1909.  Of  these  the  years 
of  the  last  decade  will  probably  have  falls  to  their  credit 
after  a  time,  since  the  record  of  falls  usually  lags  somewhat 
behind  their  occurrence.  The  largest  number  of  falls 
shown  in  any  year  during  the  period  is  n  in  1868.  The 
years  1865,  1877,  and  1886  show  7  each.  All  the  other  years 
show  from  i  to  6  falls  each.  The  full  record  by  years 
beginning  with  1800  is  as  follows: 

I8OO O  1817 O  1834. 2  1851 2 

1801 o  1818 3  1835 3  1852 4 

1802 i  1819 2  1836 3  1853 3 

1863 3  1820 i  1837 i  1854 i 

1804 2  1821. i  1838 5  1855 4 

1805 2  1822 5  1839 o  1856 3 

1806 i  1823 2  1840 3  1857 6 

1807 .  2  1824 3  1841 3  1858 4 

1808 3  1825 2  1842 3  1859 5 

1809 o  1826 2  1843 5  1860 5 

1810 2  1827 3  1844 3  1861 3 

1811 2  1828 i  1845 3  1862 2 

1812 4  1829 3  1846 4  1863 6 

1813 2  1830 2  1847 2  1864 3 

1814 2  1831 2  1848 3  1865 7 

1815........  2  1832 o  1849 i  1866 6 

1816 o  1833  i  1850 2  1867 2 

37 


38  METEORITES 


1869  .  .  . 

.  .  6 

1880 

3 

1891 

2 

IQO2 

c 

1870  

i 

1881  .  .. 

.  .   2 

1892 

-I 

IQO'? 

i 

1871  
1872  
1873  
1874  

l8?q 

•••  3 
...  4 

•••  3 

•-•  5 

c 

1882  
1883  
1884  
1885  
1886 

...  4 

•  •  •  3 
•••  3 

-  -  •  4 

7 

1893  
1894  
1895  
1896  
1807 

.  .  .  4 
-••  3 
•-•  3 

'••  * 

1904  
1905  
1906  

1907  
IQO8 

•-•  3 
.  .  .  o 
i 
o 

1876 

c 

1887  . 

6 

1808 

1 

IQOQ 

o 

1877.  . 

7 

1888.. 

o 

1800.  . 

e 

1878 5         1889 5         1900 3  350 

This  record  on  the  whole  seems  to  indicate  a  comparatively 
uniform  supply  of  meteorites,  which  is  the  more  remarkable 
when  one  considers  the  various  chances  affecting  the  observa- 
tion of  their  fall.  The  record  seems  to  afford  no  evidence 
of  cycles  or  periodicity.  As  already  remarked,  a  large 
allowance  for  unrecorded  meteorites  must  be  kept  in  mind. 
Yet  that  those  recorded  are  probably  typical  of  the  whole 
seems  to  be  indicated  by  the  fact  that  while  opportunities 
for  observation  of  meteorite  falls  have  probably  continually 
increased  since  1800,  the  record  by  decades  shows  the  decade 
from  1860  to  1870  to  considerably  exceed  in  number  of  falls 
either  of  the  two  succeeding  ones. 

Passing  from  the  falls  by  years,  the  falls  by  months  may 
be  examined.  Such  an  examination  should  have  an  especial 
significance  in  showing  the  relations  which  meteorites  may 
have  to  well-known  star  showers.  Two  of  the  best  known 
of  these  showers  occur  in  August  and  November.  If 
meteorites  are  related  to  these,  these  months  should  show  a 
larger  fall  than  others.  If  meteorites  are  not  related  to 
these,  no  special  increase  for  these  months  should  be  shown. 

On  compiling  the  results  it  is  found  that  the  months  of 
May  and  June  exhibit  the  greatest  number  of  falls.  The 
number  for  November  falls  below  the  average  and  that  for 
August  rises  only  slightly  above.  The  evidence  from  this 
record  is  therefore  that  meteorites  are  not  related  to  the  best 
known  star  showers.  It  is  fair  to  presume  that  the  record 
by  months  will  be  somewhat  influenced  by  the  times  that 
observers  are  most  abroad.  Most  of  the  observations  of 
meteorite  falls  are  made  in  the  northern  hemisphere  and  in 
this  hemisphere  observers  are  more  likely  to  be  out  of  doors 
and  hence  more  likely  to  observe  the  fall  of  meteorites  in  the 


TIMES   OF   FALL  39 

summer  than  in  the  winter  months.  The  record  shows  that 
as  a  whole  the  number  of  falls  recorded  is  less  for  the  winter 
than  the  summer  months,  yet  the  number  of  falls  cannot  be 
influenced  by  that  alone  since  the  high  record  for  May  and 
June  drops  to  nearly  half  that  number  in  July.  Further 
the  months  of  August,  September,  and  October  are  equally 
favorable  as  regards  weather  for  observations  of  .meteorite 
falls  with  those  of  April,  May,  and  June,  yet  the  latter  period 


40 


30 


I    5    I    I    i    I    i    I    §    §    I    § 

FIG.  9. —  Curve  of  meteorite  falls  by  months. 

much  excels  in  number  of  falls.  The  excess  of  falls  in  May 
and  June  must,  therefore,  be  due  to  other  causes  than  favor- 
able conditions  of  observation  and  seems  to  indicate  that 
in  the  portion  of  the  earth's  orbit  passed  through  in  these 
months  there  is  an  unusual  number  of  meteorites.  The 
full  table  up  to  1910  for  the  different  months  is  as  follows: 

Jan.    Feb.     Mar.    April    May    June     July     Aug.     Sept.     Oct.     Nov.    Dec. 
25         24         22         32         44        45         23         36         30         24         24       21=350 

This  record  is  shown  graphically  in  the  accompanying 
diagram  (Fig.  9). 

Comparison  of  the  falls  of  meteorites  by  months  as  here 
given,  with  those  of  falling  stars  and  fireballs  as  given  by 


40 


METEORITES 


W.  H.  Pickering,*  shows  a  marked  difference  of  distribution. 
According  to  Pickering's  list  the  falling  stars  and  fireballs 
are  much  more  uniformly  distributed  through  the  year  than 
are  meteorites,  and  their  period  of  greatest  number  is  from 
July  to  November.  In  May  and  June  their  number  is  at 
its  minimum.  Hence  the  record  seems  to  show  a  difference 
in  character  between  meteors  and  meteorites  and  furnishes 
per  se  a  ground  for  questioning  the  gradation  that  has  been 
supposed  to  exist  between  meteors  and  meteorites. 

Tabulation  of  meteorite  falls  by  days  of  the  year  seems 
to  show  little  of  significance.  The  largest  number  of  falls 
for  any  one  day  is  5  on  October  13,  and  this  is  a  month  when 
the  total  number  of  falls  is  not  large.  Four  days  show  4 
falls  each,  and  158,  or  nearly  half  the  total  number,  no  falls 
at  all.  The  days  without  falls  seem  to  be  scattered  indis- 
criminately through  the  year,  without  marked  grouping  or 
arrangement.  The  days  showing  falls  aside  from  those  men- 
tioned, have  from  one  to  three  falls  each,  but  do  not  show 
any  marked  grouping.  Such  a  record  seems  also  to  indicate 
that  to  refer  a  meteorite  falling  on  the  day  of  a  star  shower 
to  such  showers  is  unsafe  practice,  especially  if  the  observa- 
tions are  not  sufficient  to  assign  the  two  to  the  same  radiant. 
The  meteorite  falls  are  so  uniformly  distributed  throughout 
the  year  that  the  two  occurrences  might  easily  be  coincident 
without  being  otherwise  related.  The  full  record  of  the 
falls  by  days  up  to  1910  is  as  follows: 


Jan.     Feb.  Mar.  Apr.  May  June  July  Aug.  Sept.  Oct.  Nov.   Dec. 


2.  . 

3-- 
4-- 

I'-' 

s'.. 

9-- 
10. . 
ii. . 

12.  . 
I3-- 


:i:: 


Popular  Astronomy,  1909,  17,    277. 


TIMES   OF   FALL  41 

Jan.  Feb.  Mar.  Apr.  May  June  July  Aug.  Sept.  Oct.  Nov.  Dec. 


17  

I             I 

3         i 

2 

i 

18  

3                   i 

2 

I             I 

i 

IQ 

2 

121 

-2                 I 

I          .  .            2 

i 

*7  
20  

I 

I             I 

J 

3         2 

i 

I 

21 

I 

I            2 

I            2 

T 

22  

I 

3         i 

i         i 

3         i 

2 

2^ 

•2 

j 

j 

i       .  .         i 

24  

J 

I             I 

2 

2 

i         i 

.  . 

25  

2 

i         3       •• 

I             I 

I            2 

i 

I 

26  

..        ..         3 

2            I 

ill 

27  

I 

i         i 

2 

I 

i       ••         3 

2 

28  

I 

I            2 

i         3 

29  

I 

I          .  .             I 

i 

3 

i 

30  

I 

i         i 

i 

4 

•21  .  . 

2 

I 

i 

i 

23    23    21    29    41    42    21    32    28    24    23    203=27 

Of  all  times  of  fall  of  meteorites  the  most  satisfactory  for 
study  are  probably  the  hours  of  fall,  since  the  ratio  of  num- 
ber of  falls  to  number  of  hours  is  larger  than  that  to  days, 
months,  or  years.  While  the  hour  of  fall  is  not  known  of 
as  many  meteorites  as  is  the  year  and  month,  yet  of  273 
sufficiently  satisfactory  records  are  available.  Of  these  273 
falls,  184  occurred  in  the  time  from  noon  to  midnight,  and 
89  from  midnight  to  noon.  The  record  in  full  is  as  follows, 
the  total  number  being  less  by  seven  than  that  recorded  for 
forenoon  and  afternoon,  since  of  these  seven  the  hour  is  not 
known : 

Hours 12       i       2       3       45       6       7       8      91011         Total 

A.  M i       2       3       2      6      7       7     18     12     10      9     12     =       89 

p.  M 24     13     19     33     21     15     ii       8     1 6       7      9       3     =     176 

This  record  is  shown  graphically  in  the  accompanying 
diagram  (Fig.  10). 

As  in  the  case  of  the  months  and  the  years,  it  is  quite 
likely  that  here  also  considerable  allowance  should  be  made 
for  conditions  of  observation.  It  is  reasonable  to  expect 
that  the  number  of  falls  recorded  in  the  early  morning  hours 
would  be  less  than  that  for  other  times,  since  mankind  is 
generally  asleep  then.  That  some  such  allowance  must  be 
made  is  indicated  by  the  records,  for  the  number  of  falls 
from  midnight  to  6  A.  M.  is  only  21,  while  from  6  A.  M.  to 
noon  it  is  68.  From  noon  to  6  P.  M.  it  is  124  and  from  6  p.  M. 
to  midnight  60. 


42 


METEORITES 


35 
34 
33 
32 
31 
30 
29 
28 
27 
26 
25 
24- 
23 
22 
21 
20 
19 
IS 
17 
16 
15 
U 
13 
12 
II 
10 
9 
8 
7 
6 
5 
4 

3 

z 

\ 


12     I       2     3      4-      5     6     7     8      9     10     II    12     I     2      3      4     5     6     7     8      9     10    If     12 
A     M.  P.  M. 

FIG.  10. —  Curve  of  meteorite  falls  by  hours. 


TIMES   OF   FALL  43 

The  hours  of  fall  are  chiefly  significant,  however,  in 
indicating  the  direction  of  movement  of  meteorites.  It 
will  be  seen  from  the  accompanying  diagram  (Fig.  n)  that 
all  meteorites  reaching  the  earth  between  noon  and  mid- 
night must  be  moving  in  the  same  direction  as  the  earth  in 
its  orbit.  These  are  said  to  have  direct  motion.  Those 


svm 


FIG.  II. —  Diagram  showing  relation  of  time  of  day  and  direction  of  earth  motion 
to  velocities  of  meteorites. 

reaching  the  earth  between  midnight  and  noon  however, 
must  be  moving  in  a  direction  opposite  to  that  of  the  earth 
or  so  slowly  that  they  are  overtaken  by  it.  Those  moving 
opposite  to  the  earth  are  said  to  have  retrograde  motion. 
It  will  be  seen  that  meteorites  with  direct  motion  must 
reach  the  earth  by  overtaking  it  (or  being  overtaken  by  it) 
while  those  with  retrograde  motion  meet  the  earth. 

These  differences  in  direction  of  motion  must  produce 
great  differences  in  the  velocity  with  which  meteorites  strike 
the  earth,  since  those  overtaking  the  earth  have  the  earth's 
velocity  subtracted,  while  those  meeting  the  earth  have 


44  METEORITES 

the  earth's  velocity  added  to  theirs.  The  earth's  velocity 
about  the  sun  is  18.5  miles  per  second.  All  meteorites 
which  move  in  orbits  which  are  parabolic  about  the  sun 
have  a  velocity  of  26.16  miles  per  second.  If,  therefore,  a 
meteorite  having  this  velocity  overtakes  the  earth  it  will 
strike  with  a  velocity  of  only  7.7  miles  per  second,  its  velo- 
city minus  that  of  the  earth.  On  the  other  hand  a  meteor- 
ite moving  in  the  opposite  direction  with  parabolic  velocity 
and  meeting  the  earth  will  strike  with  its  own  velocity  plus 
that  of  the  earth,  or  44.7  miles  per  second.  To  these  velo- 
cities must  be  added  that  produced  by  the  earth's  attraction. 
It  has  been  shown  by  Lowell*  that  this  may  be  as  great  as 
2.66  miles  per  second  and  can  not  be  less  than  0.53  miles  per 
second.  The  greatest  velocity  then  at  which  a  meteorite 
can  strike  the  earth  is  44.7+2.7  =  47.4  miles  per  second,  and 
the  least,  if  the  meteorite  has  direct  motion,  is  7.7+0.5  =  8.2 
miles  per  second.  Such  differences  in  velocities  must  have 
a  marked  effect  on  meteorites.  Meteorites  passing  into  the 
earth's  atmosphere  at  the  higher  velocity  must  be  subjected 
to  far  greater  heat  and  friction  than  those  moving  at  the 
lower  velocity.  The  greater  heat  and  friction  would  prob- 
ably be  sufficient  to  burn  up  all  but  the  largest  meteorites, 
and  this,  as  Newtonf  and  W.  H.  PickeringJ  have  both  re- 
marked, may  be  the  principal  reason  why  so  small  a  number 
of  meteorites  is  known  to  fall  between  midnight  and  noon. 
According  to  the  records  above  given  more  than  twice  as 
many  meteorites  fall  from  noon  to  midnight  as  from  mid- 
night to  noon.  This  would  indicate  that  most  meteorites 
are  moving  in  their  orbits  in  the  same  direction  as  the  earth, 
but  taking  into  consideration  the  lack  of  favorable  oppor- 
tunity for  observation  of  meteorites  with  retrograde  motion 
on  account  of  the  time  of  their  fall  and  taking  into  consid- 
eration the  greater  liability  that  they  will  be  burned  up  on 
account  of  their  greater  velocity,  it  is  possible  that  the  dif- 
ference in  quantity  of  meteorites  of  the  two  classes  is  not  as 
great  as  appears  at  first  sight. 

*Science,  N.  S.,  1909,  30,  339. 
fAm.  Jour.  Sci.,  1888,  3,  36,  10. 
^Popular  Astronomy,  1910,  18,  264. 


TIMES   OF   FALL  45 

A  study  of  the  table  shows  that  the  falls  are  much  more 
numerous  at  some  hours  than  others.  They  are  most 
numerous  at  3  P.  M.,  but  are  also  abundant  about  noon  and 
about  7  A.  M.  Haidinger  in  1867*  gave  the  hours  of  178 
meteorite  falls  which  may  serve  for  comparison  with  the 
above  table.  Omitting  from  Haidinger's  table  about  40 
falls  which  are  now  known  to  be  unreliable,  his  results  are 
as  follows: 

12       i       23       45       6789       10       ii       Total 

A.  M i       i       i       2      3       3       4     10      5       5         5       17     =     57 

p.  M 7      9      9     16     15       7       5       7       3       o        o         3      =     81 

Here  likewise  the  afternoon  falls  are  seen  to  be  more 
numerous  than  the  morning  falls,  and  the  number  is  greater 
at  7  A.  M.,  n  A.  M.,  and  3  p.  M.  Thus  the  numbers  of  falls 
at  different  hours  seem  to  retain  about  the  same  propor- 
tion when  different  yearly  periods  are  compared. 

On  the  whole  the  study  of  the  times  of  fall  of  meteorites 
seems  to  show  (i)  that  they  differ  considerably  from  mete- 
ors in  times  of  fall,  (2)  that  they  are  not  noticeably  related 
to  any  of  the  well  known  .star  showers,  and  (3)  that  the  rate 
of  their  supply  to  the  earth  is  remarkably  uniform. 

*Sitzb.  Akad.  der  Wiss,  Wien,  Bd.  55. 


CHAPTER  V 

METEORITE   SHOWERS 

A  striking  feature  of  some  meteorite  falls  (striking  in  more 
ways  than  one),  is  the  fact  that  a  large  number  of  in- 
dividuals, sometimes  thousands,  fall  at  one  time  and  place. 
Such  occurrences  are  called  meteoritic  showers,  and  present 
phenomena  of  much  interest.  These  showers  have  taken 
place  on  various  parts  of  the  globe  and  at  various  times 
without  any  seeming  regularity  or  relation. 

Three  of  the  largest  showers,  those  of  Estherville,  Forest, 
and  Homestead,  took  place  within  the  boundaries  of  the 
State  of  Iowa,  and  three  others,  Knyahinya,  Mocs,  and 
Pultusk,  fell  in  Hungary  or  the  neighboring  Poland.  The 
phenomena  of  violent  sounds  and  brilliant  light  which 
usually  accompany,  the  fall  of  a  meteorite  are  generally 
intensified  in  the  case  of -these  showers,  though  not  always 
to  a  marked  degree.  The  phenomena  attending  the  shower 
of  Homestead,  described  on  pages  16  to  18  may  be  con- 
sidered typical  of  the  more  violent  form.  The  distribution 
of  the  stones  of  these  showers  is  usually  over  an  elliptical 
area  with  the  longest  axis  of  the  ellipse  in  the  direction  of 
movement  of  the  meteor  (Fig.  12).  The  greatest  distance 
along  which  the  individuals  of  a  shower  have  been  observed 
to  be  distributed  in  this  way  is  sixteen  miles.  This  was  the 
distribution  of  the  Khairpur  shower. 

The  distribution  of  this  and  other  showers  is  as  follows.* 

miles 


Limerick.  .  .  . 

.    3       miles  long 

Butsura.  .  .  . 

.    3       miles  x  0.6  mile 

Holbrook... 

-   3 

x  0.6 

Pultusk  

.   5 

X   I 

Barbotan  .  .  . 

.   6 

long 

Homestead.  . 

.  7 

x  4      m   es 

L'Aigle  

-  1% 

X  2^ 

Stannern.  .  .  . 

.   8 

x  3 

Estherville.  . 

.   8 

KlX 

Pillistfer.  .  .  . 

.   8 

X2*4 

Mocs  

•  9 

X  2 

.Knyahinya.  ...   9      m 
Weston  10 
Hessle  10 
New  Con  cord..  10 
Castalia  10 
Macao               14 

les  x  3 
long 

*  3 
x  3 
lone 

Cold 
Bokkeveld.  .16 
Khairour.  .    .  .  16 

RWMg 

X   I 

X  1 

mile 
miles 


*Chiefly  from  Fletcher,  Min.  Mag.,  1889,  8,  225. 

46 


METEORITE   SHOWERS 


47 


\Vv\\o. 


FIG.  12.  —  Distribution  of  the  individuals  of  the  Homestead,  Iowa,  meteorite 
shower.  The  shower  moved  from  south  to  north,  the  larger  individuals  being 
carried  farther  by  their  greater  momentum.  The  squares  in  the  diagram 
represent  a  square  mile  each. 


48  METEORITES 

Another  feature  to  be  noted  in  the  distribution  of  the 
individuals  of  such  showers  is  that  of  assortment  according 
to  size.  The  smaller  individuals  fall  at  the  end  of  the 
ellipse  nearest  the  point  from  which  the  movement  comes, 
the  larger  ones  at  the  end  farthest  away.  This  difference 
is  probably  due  to  the  fact  that  the  greater  momentum  of 
the  larger  masses  carries  them  farther.  This  rule  would 
seem  to  be  of  universal  application  and  any  apparent  re- 
versal of  it,  such  as  has  sometimes  been  reported,  may  per- 
haps be  explained  as  a  failure  to  determine  the  true  direction 
of  movement  of  the  meteor. 

With  a  few  unimportant  exceptions,  the  individuals  of  a 
shower  are  of  the  same  nature.  Single  individuals  of  the 
Homestead,  Stannern,  and  Pultusk  showers  were  of  a  some- 
what different  character  from  the  rest  but  not  markedly  so. 
In  the  Estherville  shower  gradations  from  iron-stones  to 
irons  were  seen.  At  Brenham  also  both  iron-stones  and 
irons  fell. 

All  observed  showers  have  been  of  stones,  but  the  finding 
of  numerous  individuals  of  iron  in  single  localities  such  as 
Toluca  and.  Canyon  Diablo  indicates  that  showers  of  mete- 
oric irons  sometimes  take  place  also. 

Finding  of  stones  or  irons  in  large  quantity  at  any  lo- 
cality may  be  assumed  to  show  the  former  occurrence  of  a 
shower.  Showers  of  stones  that  have  either  been  observed 
or  found  took  place  at  Barbotan,  Cronstadt,  Estherville, 
Forest,  Futtehpore,  Hessle,  Holbrook,  Homestead,  Jonzac, 
Killeter,  Knyahinya,  L'Aigle,  Macao,  Mezo-Madarasz, 
Mocs,  Orgueil,  Pultusk,  Siena,  Stannern,  and  Weston. 
Showers  of  irons  occurred  at  Brenham,  Canyon  Diablo, 
Coahuila,  Great  Nama  Land,  Imilac,  Inca,  and  Toluca. 
Numerous  other  falls,  while  not  producing  a  sufficient 
number  of  individuals  to  constitute  a  shower,  yet  afforded 
many  stones.  Thus  many  stones  fell  at  Admire,  Agen, 
Aleppo,  Borgo  San  Donino,  Cold  Bokkeveld,  Dhurmsala, 
Kesen,  Khairpur,  Madrid,  Manbhoom,  Modoc,  Monte 
Milone,  Ness  County,  Nulles,  Ochansk,  Sokobanja,  Tomat- 
lan  and  Toulouse.  At  Chail,  Grazac,  Khetree,  Jelica, 
New  Concord,  Ploschkowitz,  and  Segowlee  from  20  to  40 


METEORITE   SHOWERS  49 

stones  fell;  at  Zsadany  16,  at  Stalldalen  n,  at  Blansko  8,  at 
Bandong  and  Lance  6,  at  Barratta,  Bremervorde,  Butsufa, 
and  Drake  Creek  5,  at  Harrison  County,  Marion  and  Lissa  5, 
and  at  numerous  other  localities  2  to  3  stones.  Of  irons, 
about  15  individuals  are  known  from  Glorieta;  4  to  6  from 
Smith ville,  Staunton,  Steinbach,  Trenton,  and  Youndegin: 
3  from  Arispe,  Bischtiibe,  and  Crab  Orchard;  and  2  from 
Braunau,  Chupaderos,  Cosby  Creek,  Hraschina,  Losttown, 
and  Tucson. 

It  is  highly  probable  that  at  many  of  the  above  localities 
not  all  the  individuals  which  fell  were  found,  so  that  the 
numbers  would  be  increased  if  the  full  complement  were 
known. 

The  number  of  stones  falling  in  some  of  these  showers  is 
remarkable.  In  each  of  the  showers  of  Pultusk  and  Mocs 
more  than  100,000  stones  fell.  In  the  shower  of  Holbrook 
14,000  stones  fell,  and  in  that  of  L'Aigle  2-3,000.  The  total 
quantity  of  meteoric  matter  falling  in  a  single  shower  is 
also  often  large  though  not  larger  than  some  single  stones. 
In  the  Knyahinya  shower  the  stones  of  which  were  rela- 
tively large,  over  423  kilos  (840  pounds)  fell.  From  Hol- 
brook 218  kilos  were  obtained  and  about  the  same  quan- 
tity from  Pultusk. 

The  question  of  the  amount  of  area  over  which  meteorites 
of  a  shower  may  be  distributed  becomes  of  considerable  im- 
portance when  considered  in  relation  to  meteorites  found. 
If  showers  can  distribute  meteorites  over  areas  covering 
scores  or  hundreds  of  miles,  meteorites  of  similar  characters 
found  within  such  areas  should  be  referred  to  one  fall  in- 
stead of  many.  This  is  an  especially  important  considera- 
tion in  regard  to  the  iron  meteorites  of  the  class  of  medium 
octahedrites,  since  many  of  them  are  separated  in  point  of 
fall  by  less  than  a  hundred  miles  and  yet  are  regarded  of 
distinct  origin.  Earlier  writers  were  inclined  to  group  into 
one  fall  all  similar  meteorites,  even  though  separated  by 
thousands  of  miles  of  distance,  but  later  observations  have 
failed  to  confirm  this  view.  Until  an  observed  shower  can 
be  seen  to  disperse  meteorites  for  great  distances  we  seem 
compelled  to  allow  but  slight  dispersion  by  a  shower.  Two 


50  METEORITES 

important  meteoric  finds,  however,  seem  to  be  exceptions  to 
this  rule.  These  are  Coahuila  and  Great  Nama  Land. 

In  the  state  of  Coahuila,  Mexico,  numbers  of  meteoric 
irons  of  the  rare  class  of  hexahedrites  are  found  one  or  two 
hundred  miles  apart.  It  hardly  seems  likely  that  separate 
falls  of  these  rare  meteorites  would  occur  within  such  a  lim- 
ited area,  and  the  only  alternative  seem  to  be  to  ascribe 
them  to  a  shower  or  to  assign  their  distribution  to  human 
agency.  Fletcher  after  an  exhaustive  study  concluded  that 
it  was  highly  probable  that  the  usefulness  of  these  masses 
of  iron  for  anvils  and  other  artificial  purposes  caused  their 
wide  distribution  by  man.  The  irons  of  Great  Nama  Land 
are  also  of  a  peculiar  class,  being  fine  octahedrites.  They 
have  been  found  in  various  places  over  an  area  whose  far- 
thest limits  are  about  fifty  miles  apart.  Here  again  it  seems 
highly  probable  that  distribution  by  man  has  taken  place. 

Opinions  differ  as  to  whether  the  individuals  of  a  shower 
are  separated  before  striking  the  earth's  atmosphere  or 
come  from  a  single  mass  broken  up  in  its  passage  through  the 
atmosphere.  Some  breaking  up  of  individuals  is  known  to 
take  place  in  the  atmosphere,  because  individuals  show 
various  stages  of  crust  formation  on  different  surfaces. 
This  crust  varies  from  a  deep  alteration  to  a  mere  smoking, 
and  such  differences  could  only  arise  from  successive  frac- 
tures and  successively  shorter  periods  of  exposure.  But  the 
majority  of  individuals  of  a  shower  are  thoroughly  encrusted 
on  arrival  at  the  earth  and  are  often  oriented  (Fig.  13). 
Hence  they  must  have  had  a  nearly  uniform  period  of  flight 
through  the  atmosphere.  As  Cohen  suggests,*  this  could 
only  be  the  case  if  the  breaking  up  took  place  simultaneously 
and  very  soon  after  the  entrance  of  the  mass  into  the 
atmosphere.  Now,  if  conditions  favor  such  a  breaking  up  at 
the  beginning  of  the  atmospheric  course,  it  is  not  easy  to 
see  why  meteoric  showers  are  not  more  abundant,  since 
meteoric  stones  do  not  differ  greatly  in  structure  and 
composition.  A  breaking  up  of  the  soft,  carbonaceous 
meteorites  would  be  especially  probable.  Moreover,  while 
the  breaking  up  of  stones  in  the  atmosphere  can  be  con- 

*  Meteoritenkunde,  Heft  II,  186. 


METEORITE   SHOWERS 


51 


FIG.  13. —  Various  individuals  of  the  Orgueil,  France,  shower.  Similar  numbers 
indicate  the  same  stone  in  different  positions.  Somewhat  reduced.  After 
Daubree. 


52  METEORITES 

ceived,  it  is  hard  to  understand  how  masses  so  tough  and 
coherent  as  the  meteoric  irons  could  readily  be  divided 
except  along  a  few  pre-existing  clefts  into  the  great  numbers 
of  individuals  seen  in  the  Toluca  and  Canyon  Diablo 
meteorites  for  example. 

The  principal  objections  to  the  view  that  the  individuals 
of  a  meteoritic  shower  are  largely  separated  before  reaching 
the  earth's  atmosphere  seem  to  be  those  urged  by  Daubree, 
that  if  the  meteorites  exist  as  a  swarm  in  space  they  should 
be  seen  moving  as  a  swarm  of  lights  in  the  atmosphere,  and 
further  that  their  distribution  in  falling  should  be  much  more 
irregular  and  extensive  than  is  found  to  be  the  case.  So 
far  as  the  first  objection  is  concerned,  it  is  of  interest  to  note 
that  the  Rochester  meteorite  was  described  as  looking  like 
a  "flock  of  red-hot  birds"  moving  through  the  air.  Nu- 
merous lights  have  been  seen  in  the  case  of  other  showers. 
But  that  the  individuals  of  a  shower  should  be  distributed 
over  so  narrow  an  area  is  remarkable,  and  shows  to  what 
a  high  degree  a  fixed  direction  of  movement  may  have  been 
imparted  to  the  components  of  a  swarm. 

To  sum  up,  the  following  facts  would  lead  us  to  assume 
that  meteorites  come  within  the  range  of  the  earth's  attrac- 
tion as  a  single  body  and  that  their  disintegration,  if  any, 
takes  place  in  the  earth's  atmosphere: 

1.  The   angularity  of  most  of  the  individuals  of  stone 
showers. 

2.  The    uniform    composition    of   the    individuals    of   a 
shower. 

3.  The  appearance  of  meteors  in  the  air  as  a  ball  rather 
than  as  a  swarm  of  bodies. 

4.  The    narrow    distribution    of   the    components    of    a 
shower. 

On  the  other  hand  the  following  facts  seem  to  favor  the 
assumption  that  meteorites  which  fall  as  showers  existed  as 
a  swarm  in  space: 

1.  The   complete   encrusting   of  most    individuals   of   a 
shower. 

2.  The  small  number  of  showers. 

3.  The  regular  form  of  the  area  over  which  a  shower  dis- 


METEORITE   SHOWERS  53 

tributes  itself  and  the  regular  distribution  of  the  individuals 
over  it. 

4.  The  difficulty  of  breaking  up  iron  masses  by  atmos- 
pheric   shock. 


CHAPTER  VI 

SIZE   OF   METEORITES 

The  largest  individual  meteorite  known  is  one  of  the  Cape 
York,  Greenland  group  (Fig.  14).  It  is  an  iron  meteorite 
weighing  36^  tons.  Its  principal  dimensions  are:  Length, 
10  feet,  II  inches;  height,  6  feet,  9  inches;  width,  5  feet,  2 
inches.  The  meteorite  had  long  been  known  as  a  mass  of 
iron  to  the  natives  of  the  region  where  it  occurred,  but  it 
had  not  been  seen  by  white  men  until  Lieut.  Peary  visited 
it  in  1895.  It  lay  on  the  shores  of  Melville  Bay,  35  miles 
east  of  Cape  York,  Greenland.  The  Esquimaux  had 
christened  it  "Ahnighito,"  meaning  the  "Tent,"  in  allusion 
to  its  shape  and  size.  About  four  miles  away,  lay  two  other 
large  iron  meteorites  which  were  undoubtedly  individuals 


I 


FIG.  14. —  Cape  York,  Greenland,  the  largest  known  meteorite.   Weight,  36^2  tons. 

54 


SIZE   OF   METEORITES  55 

of  the  same  fall.  All  of  these  meteorites  were  brought  to 
New  York  City  by  Lieut.  Peary  in  1895  and  1897. 

The  next  largest  meteorite  to  "Ahnighito"  is  that  of  Ba- 
cubirito,  Mexico  (Frontispiece).  This  is  also  an  iron  mete- 
orite. While  it  has  not  been  weighed,  its  estimated  weight 
is  27  tons.  Its  dimensions  as  given  by  H.  A.  Ward,  are: 
Length  13  feet,  I  inch;  width,  6  feet,  2  inches;  thickness,  5 
feet,  4  inches.  As  its  shape  is  much  less  compact  than  that 
of  the  large  Cape  York  individual,  these  dimensions  are  not 
of  much  service  in  comparing  the  masses  of  the  two  bodies. 
The  existence  of  this  meteorite  had  perhaps  long  been  known 
to  white  men,  but  it  was  first  brought  to  scientific  notice  by 
Prof.  Barcena  in  1876.  Later  the  meteorite  was  visited  and 
described  by  Prof.  H.  A.  Ward.  The  mass  has  never  been 
moved  from  the  locality  in  the  state  of  Sinaloa,  Mexico, 
where  it  originally  fell. 

Two  masses  of  meteoric  iron  from  Chupaderos,  Mexico, 
which  together  weigh  about  26  tons,  must  be  placed  next 
in  the  scale  of  size.  Although  these  two  masses  were  found 
a  few  hundred  feet  apart,  the  character  of  their  surface 
showed  that  they  were  a  single  mass  before  falling.  The 
dimensions  of  this  mass  were:  Length,  12  feet;  width,  7  feet. 
As  separated,  one  of  the  masses  had  about  twice  the  weight 
of  the  other.  These  irons  were  first  located  by  Europeans 
as  early  as  1582  and  were  removed  by  the  Mexican  Gov- 
ernment to  the  City  of  Mexico  about  1880. 

Following  these  masses  in  size  comes  that  of  Willamette, 
Oregon,  an  iron  whose  present  weight  is  about  15^  tons 
but  the  original  weight  of  which  was  undoubtedly  much 
larger.  The  dimensions  of  the  mass  are:  Length,  10  feet, 
3^2  inches;  breadth,  6  feet,  6  inches;  height,  4  feet,  3  inches. 
The  mass  is  conical  in  shape  and  lay  for  an  unknown  length 
of  time  in  a  dense  forest  with  its  base  uppermost.  The 
climate  being  very  moist,  conditions  were  favorable  for  a 
rapid  oxidation  and  decomposition  of  the  iron  and  as  a 
result  great  cavities  (Fig.  15),  were  formed  in  the  mass  which 
have  considerably  decreased  its  original  weight.  The  size 
of  one  of  these  cavities  is  described  by  Ward  as  3  feet  long 
by  10  to  15  inches  across  and  with  an  average  depth  of  16 


56 


METEORITES 


inches.     Many  other  such  cavities  of  nearly  equal  size  occur. 
This  mass  was  moved  to  New  York  City  in  1906. 

An  iron  meteorite  of  a  similar  form  to  Willamette  but 
smaller  and  little  if  any  affected  by  decomposition  is  that 
of  El  Morito  (San  Gregorio),  Mexico,  the  weight  of  which 
is  about  II  tons  (Fig.  16).  The  dimensions  of  this  meteor- 
ite are:  Length,  6  feet,  6  inches;  height  5  feet,  6  inches; 


FIG.  15. —  The  Willamette  meteorite  showing  cavities  produced  by  terrestrial 
erosion  and  solution. 

breadth,  4  feet.  The  existence  of  this  iron  was  known  as 
early  as  1600  and  in  1821  a  Spanish  inscription  was  cut  on  it 
which  (translated)  read:  "Since  no  one  in  the  world  could 
make  it,  only  God  with  his  power  this  iron  can  destroy." 
About  1880  the  meteorite  was  removed  with  several  others 
to  the  City  of  Mexico. 

Between  this  and  the  meteorite  next  in  size  a  considerable 
gap  in  weight  intervenes.  The  Bendego,  Brazil,  meteorite 
which  comes  in  this  place,  weighs  only  about  5  tons.  It  is  of 
a  flattened,  forked  shape,  its  extreme  dimensions  being: 
Length,  7  feet;  width,  4  feet;  thickness,  2  feet.  The  meteor- 
ite is  said  to  have  been  discovered  in  1784  but  was  not 
described  till  1816.  In  1888  it  was  moved  to  Rio  Janeiro. 


SIZE    OF    METEORITES 


57 


The  next  largest  meteorite  in  size  comes  from  Australia, 
and  is  known  as  Cranbourne.  Several  masses  occur  of  this 
fall,  of  which  the  largest  weighs  nearly  4  tons.  It  is  of 
rounded  form  and  is  now  in  the  British  Museum. 

Next  in  weight  ranks  another  Mexican  iron  found  not  far 
from  those  of  Chupaderos.  This  is  known  as  Adargas  or 
Concepcion.  It  is  of  flattened  form  and  has  the  dimensions: 


FIG.  16. —  El  Morito,  Mexico,  meteorite.     Weight,  n  tons 

Length,  3  feet,  10  inches;  breadth,  3  feet,  I  inch;  thickness^ 
i  foot,  2  inches.  Its  weight  is  about  3  tons.  According 
to  an  inscription  on  the  iron  it  was  found  in  the  year  1600. 
It  is  now  in  the  City  of  Mexico. 

The  second  largest  individual  of  the  Cape  York  fall  ranks 
next  in  size.  This  is  of  conical  form  and  weighs  nearly 
3  tons.  From  its  shape  it  was  christened,  by  the  Esquimaux, 
the  "Woman." 

Another  Mexican  meteorite  comes  next  in  size.  This  is 
the  meteorite  of  Casas  Grandes,  which  was  found  carefully 
wrapped  in  coarse  linen  in  some  ancient  ruins  in  the  state  of 
Chihuahua.  It  is  of  lenticular  form  and  has  the  dimensions: 


58  METEORITES 

Length,  3  feet,  2  inches;  width,  2  feet,  5  inches;  height,  I  foot, 
6  inches.  The  weight  of  this  meteorite  is  nearly  2  tons,  and 
it  is  now  in  the  United  States  National  Museum. 

The  last  of  known  meteorite  individuals  whose  weight 
exceeds  I  ton  is  from  Quinn  Canyon,  Nevada.  This  is  a 
beautifully  oriented,  conical  iron  having  the  dimensions: 
Length,  3  feet,  n  inches;  breadth,  2  feet,  II  inches;  height, 
I  foot,  8  inches.  Its  weight  is  a  little  over  \]4  tons.  It  was 
found  in  1908  and  is  now  in  the  Field  Museum  of  National 
History,  Chicago. 

The  weights  of  these  masses  are  shown  in  kilograms  in 
the  following  table  as  well  as  the  cities  in  which  the  meteor- 
ites are  now  preserved. 

Weight  in  Where 

Name  Kilograms  Preserved 

Cape  York 33>IJ3  New  York 

Bacubirito 27,500  Mexico 

Chupaderos,  2  individuals  20,881  Mexico 

Willamette 14,110  New  York 

El  Morito 10,000  Mexico 

Bendego   '  5,370  Rio  Janeiro 

Cranbourne 3>73J  London 

Adargas 3>325  .....  .Mexico 

Cape  York    2,727  New  York 

Casas  Grandes !>545  Washington 

Quinn  Canyon 1A%5  Chicago 

The  above  are  all  irons,  and  except  in  one  case  single 
masses.  Other  large  iron  masses  known  are  those  of 
Magura,  weighing  1500  kilos,  Zacatecas  1000  kilos,  Charcas 
784  kilos,  and  Red  River  750  kilos.  All  of  these  exceed  in 
size  the  largest  stone  meteorite,  Long  Island,  which  weighs 
564  kilos  (1200  pounds).  Although  broken  at  the  time  of 
its  fall  this  undoubtedly  fell  as  a  single  individual.  The 
largest  unbroken  stone  meteorite  individual  known  is  one 
of  the  Knyahinya  shower,  weighing  293  kilograms  (600 
pounds).  The  mass  of  Bjurbole  fell  as  a  single  stone  weigh- 
ing about  400  kilos  (800  pounds)  but  it  was  broken  by 
striking  the  earth.  The  iron  meteorites  will  be  seen  from 


SIZE   OF   METEORITES  59 

the  above  statements  to  far  outweigh  the  stone  meteorites 
in  the  size  of  single  masses,  and  this  would  be  expected  from 
the  greater  resistance  to  fracture  and  erosion  which  their 
substance  is  able  to  exert.  None  of  these  large  iron  masses 
have  been  seen  to  fall.  The  largest  single  iron  mass  seen 
to  fall  is  that  of  Cabin  Creek,  weighing  about  100  pounds. 

From  large  masses  all  gradations  of  size  occur  .down 
to  material  of  microscopic  dimensions.  Some  meteoric 
showers  produce  large  numbers  of  small  stones,  others  only 
large  ones.  In  the  shower  of  Holbrook  it  was  estimated 
that  over  a  thousand  individuals  of  the  size  of  grape  seeds 
fell.  Individuals  smaller  than  this  are  not  likely  to  be 
found,  but  it  is  theoretically  certain  that  they  are  formed. 


CHAPTER  VII 

FORMS   OF   METEORITES 

The  forms  of  meteorites  seem  to  depend  chiefly  on  the 
amount  of  shaping  which  they  undergo  in  their  passage 
through  the  earth's  atmosphere.  This  may  in  turn  depend 
partly  on  their  speed  of  fall,  a  lower  velocity  giving  a  longer 
time  for  shaping.  The  amount  of  shaping  seems  to  be 
independent  of  the  size  of  the  masses,  since  large  and 
small  individuals  show  similar  forms.  It  is  also  largely 
independent  of  the  substance  of  the  meteorites,  but  there 
are  some  forms  acquired  by  iron  meteorites  which  are  hardly 
possible  to  stone  meteorites.  Meteorites  which  break  up 
shortly  before  reaching  the  earth  present  irregular  forms 
such  as  a  rock  broken  by  a  hammer  might  show.  A  longer 
course  through  the  atmosphere  gives  an  opportunity  for 
shaping  the  masses,  under  the  operation  of  which  certain 
characteristic  forms  are  produced.  These  forms  may  be 
enumerated  as  follows:  Cone-shaped  or  conoid,  shield- 
shaped  or  peltoid,  shell-shaped  or  ostracoid,  bell-shaped  or 
codonoid,  pear-shaped  or  onchnoid,  column-shaped  or  sty- 
loid,  ring-shaped  or  cricoid,  and  jaw-shaped  or  gnathoid; 
while  among  angular  forms  may  be  observed  cuboidal,  pyr- 
amidal, rhombohedral,  tetrahedral,  etc.,  forms. 

Of  the  above  forms  the  cone-shaped  or  conoid  is  the  most 
common  and  typical.  The  cone  of  such  forms  is  usually  low 
in  proportion  to  its  breadth,  but  its  proportions  may  so 
vary  as  to  approach  the  bell  shape  on  the  one  hand  or  the 
shield  shape  on  the  other.  The  form  is  evidently  due  to 
the  greater  exposure  of  the  forward  corners  of  the  fall- 
ing meteorite  to  the  heat  and  friction  of  the  atmosphere. 
These  corners,  as  represented  in  the  accompanying  diagram 
(Fig.  17),  are  worn  away  more  rapidly  than  interior  portions. 
From  the  edges  to  the  center  the  abrading  forces  thus  grad- 
ually lessen  in  intensity  and  a  sloping  surface  is  produced. 

60 


FORMS   OF   METEORITES 


61 


This  slope  is  usually  somewhat  rounded,  and  the  highest 
point  or  apex  of  the  cone  is  not  always  situated  at  the  geo- 
metric center  of  the  figure.  It  is  probably,  however,  gen- 
erally in  line  with  the  center  of  gravity  of  the  mass.  While 


FIG.  17.     Diagram   showing  production  .of  conical   form   in   a   meteorite   by  the 
greater  exposure  of  its  corners. 

it  is  true  that  this  conical  form  may  be  largely  the  result 
of  atmospheric  shaping,  it  is  also  true  that  a  meteorite 
originally  possessing  such  a  form  would  be  turned  by  the 
resistance  of  the  earth's  atmosphere,  as  has  been  shown 
mathematically  by  Schlichter,*  with  its  apex  foremost.  The 
subsequent  action  of  the  atmosphere  would  then  tend  sim- 
ply to  preserve  this  form. 

*Bull.  Geol.  Soc.  Am.,  1903,  14,  112-116. 


FIG.  18. —  Front  (upper  figure)  and  rear  (lower  figure)  sides  of  Cabin 
Creek  meteorite.  The  contrast  in  the  relief  of  the  two  surfaces  is 
typical  of  well-oriented  meteorites. 


FORMS   OF   METEORITES  63 

While  the  rear  side  of  such  a  meteorite  is  much  less 
affected  than  the  front,  yet  here  too  some  shaping  seems  to 
take  place,  since  it  is  usually  more  or  less  concave  as  com- 
pared with  the  convex  front  side.  A  marked  difference 
in  the  character  of  the  pittings  is  usually  also  noticeable 
between  the  front  and  rear  sides.  Those  of  the  front  side 
are  small,  deep,  and  oval  in  outline,  while  those  of  the  rear 


FIG.  19. —  Front   side   of  Goalpara    meteorite,    showing    radial    arrangement   of 
pittings.     After  Haidinger. 

side  are  broad,  shallow,  and  more  or  less  circular  (Fig.  18). 
The  crust  of  the  front  side  is  thin  and  dark  in  color;  that 
of  the  rear  side  thick,  slaggy,  and  usually  of  a  reddish 
or  brownish  hue.  The  latter  feature  shows  that  the  rear 
side  has  encountered  less  air,  since  it  indicates  less  oxidation. 
Evidence  of  the  passing  of  currents  of  air  radially  from  the 
apex  of  the  cone  is  to  be  seen  in  the  arrangement  of  the 
pittings  on  the  front  side,  (Fig.  19).  These  pits  are  as  a 
rule  elongated,  oval,  and  furrow-like,  and  broadest  on  the 
side  toward  the  edge.  The  slope  of  their  sides  is  commonly 


64  METEORITES 

unequal  and  the  position  of  the  steeper  slope  is  not  constant. 
The  pits  do  not  as  a  rule  merge  into  one  another  on  all  sides, 
but  follow  lineal  and  radial  courses.  In  size  the  pits  are 
usually  larger  on  iron  than  on  stone  meteorites,  their  aver- 
age range  being  from  one-fourth  to  one  inch  in  diameter. 
The  pits  are  not  usually  to  be  found  on  the  apex  of  the  cone, 
the  surface  there  being  characteristically  smooth.  A  char- 
acteristic feature  of  the  edge  where  the  front  and  rear  sur- 
faces of  the  meteorite  join  is  a  thickening  of  the  crust  caused 


FIG.  20. —  Jonzac  meteorite,  showing  lateral  edge  produced  by  meeting  of  currents 
from  front  and  rear. 

by  an  accumulation  of  fused  matter  (Fig.  20).  This  crust 
is  also  often  notably  blebby  in  character.  The  rear  side 
also  often  exhibits  adhering  particles  which  have  the  ap- 
pearance of  being  fragments  of  crust.  Haidinger  regarded 
these  as  fragments  which  accompanied  the  meteorite  from 
space  with  a  velocity  equal  to  it  and  fused  upon  it  when 
its  speed  was  lessened.  Rath  and  Tschermak,  however, 
thought  them  fragments  from  the  front  side  of  the  mete- 
orite which  were  thrown  to  the  rear  and  fused  upon  that 
surface  by  hot  air  streaming  into  the  space  behind. 

Many  large  meteorites,  and  especially  iron  ones,  exhibit  the 
conical  or  conoid  form  in  a  high  degree.     Among  such  large 


FORMS   OF   METEORITES 


65 


iron  meteorites  may  be  mentioned  El  Morito.  Willamette, 
(Fig.  21),  Quinn  Canyon,  and  Cabin  Creek. 

The  iron  meteorite  of  Cabin  Creek  weighs  about  100 
pounds.  Its  front  or  apical  side  is  covered  with  numerous, 
deep,  elongated  impressions  one-half  to  one  inch  in  diam- 


^Bfc*, 


FIG.  21. —  A  conoid  or  cone-shaped  meteorite.     Willamette.     Weight,  about 

15  tons. 

eter.  The  apex  is  free  of  crust,  but  from  it  fused  threads  of 
the  substance  of  the  meteorite  run  radially.  These  threads 
are  hair-like  in  thickness  and  from  one  to  four  inches  long, 
and  may  be  traced,  according  to  Kunz,  on  the  slope  and 
bottom  of  the  pits.  The  rear  face  is  relatively  flat  and 
shows  broader,  shallower  pits  than  the  front.  These  pits 


66 


METEORITES 


are  from  one  to  two  inches  in  diameter.  The  rear  surface 
has  a  rough,  scale-like  crust  about  one  millimeter  thick. 
Brezina  regards  the  thin,  smooth  crust  of  the  front  side  of 
this  meteorite  as  giving  evidence  that  it  was  in  the  state 
of  a  thin,  mobile  liquid,  while  the  thick  crust  of  the  rear 
side  shows  that  it  was  in  a  viscid  condition  and,  therefore, 
must  have  received  less  heat. 

Other  smaller  iron  meteorites  exhibiting  a  more  or  less 


FIG.  22. —  A  conoid  or  cone-shaped  meteorite.  Long  Island,  Kansas.  Stone, 
weight  about  1 100  pounds.  The  symmetrical  arrangement  of  the  pittings  is 
noteworthy. 

well-marked  conoid  form  are  Braunau,  Carlton,  Cleveland, 
and  Costilla. 

Of  stone  meteorites  the  largest  known  to  exhibit  the 
conoid  form  is  Long  Island  (Fig.  22),  the  weight  of  which 
when  entire  was  about  1400  pounds.  Here  a  smooth  apex, 
deep,  radial  pitting  of  the  front  side,  and  broad,  shallow 
pitting  of  the  rear  side  are  exhibited.  The  altitude  of  the 
cone  of  this  meteorite  is  20  inches,  and  the  greatest  diameter 
of  the  base  34  inches. 

Another. large  stone  meteorite  exhibiting  the  same  form 
is  the  large  mass  of  Bath  Furnace  (Fig.  23).  This  is  an 


FIG.  23. —  Side  (upper  figure)  and  front  (lower  figure)  views  of  the  Bath 
Furnace  meteorite.  This  is  a  well-oriented  stone  meteorite  weighing 
about  180  pounds.  The  symmetrical  arrangement  of  the  oittings  is  well 
shown. 


68  METEORITES 

individual  weighing  180  pounds  and  covered  uniformly  with 
a  black  crust.  On  the  front  side  appears  the  usual  smooth 
apex  with  rows  of  pittings  radiating  from  it.  The  rear  side 
is  relatively  smooth. 

Variation  of  the  conical  shape  produced  by  a  diminution 
of  the  altitude  of  the  cone  gives,  as  has  been  stated,  shield- 
shaped  forms.  Of  this  form  the  N'Goureyma  and  Algoma 
meteorites  furnish  excellent  examples.  Both  of  these  are 
iron  meteorites.  The  N'Goureyma  meteorite  is  22  inches 
long  and  n  inches  broad,  and  its  greatest  thickness  is  3^ 
inches.  Its  outline  seen  broadside  is  very  irregular  and  the 
boss  of  the  shield  is  placed  near  one  end.  The  front  or  boss 
side  is  convex  and  marked  by  small,  deep,  rounded  pits, 
the  walls  of  which  often  exhibit  smaller  pits  giving  them  a 
pockmarked  appearance.  Fine,  furrow-like  depressions  also 
give  this  surface  a  scale-like  semblance.  Contrary  to  the 
usual  rule,  the  crust  is  rougher  and  darker  on  the  front  than 
on  the  rear  side.  The  pits  of  the  rear  side  are  large,  shallow, 
smooth,  and  elongated.  Cohen  was  of  the  opinion*  that  the 
original  form  was  more  symmetrical,  but  that  it  was  strongly 
modified  by  the  erosion  of  the  air.  On  account  of  drift 
markings  seen  on  both  surfaces  he  also  concluded  that  the 
meteorite  moved  through  the  air  at  an  acute  angle  to  the 
direction  of  its  motion.  Hobbs,|  however,  urged  that  the 
drift  markings  on  the  rear  side  were  plainly  the  result  of  air 
currents  forced  through  two  holes  in  the  meteorite,  since 
they  were  found  only  in  the  area  peripheral  to  these  openings. 
It  is  highly  probable,  therefore,  as  Hobbs  concluded,  that 
the  meteorite  took  the  broadside  attitude  in  its  flight. 

The  outline  of  the  Algoma  meteorite  (Fig.  24),  on  its 
broadside  is  roughly  elliptical  with  axes  of  10  and  6  inches. 
Its  thickness  varies  from  about  one  inch  near  the  geometric 
center,  to  knife  edges  at  several  points.  A  few  large,  shallow 
pits  occur  upon  the  front  side,  but  a  more  remarkable  fea- 
ture is  a  complete  series  of  radial  furrows  extending  over  the 
surface  from  the  center  outward.  These  are  knife-like  edges 
from  one-fifth  to  one-tenth  of  a  millimeter  in  width  at  the 

*Am.  Jour.  Sci.,  1903,  4,  15,  254. 
fBull.  Geol.  Soc.  Am.,  1903,  14,  108. 


FORMS    OF    METEORITES  69 

base,  separated  by  furrows  from  one  to  two  millimeters  wide. 
The  ridges  are  modified  somewhat  in  their  course  by  the 
structure  of  the  meteorite,  but  in  general  pursue  a  rectilinear 
direction  with  a  slight  curve  to  the  left.  On  the  rear  side  the 
surface  is  concave  and  a  number  of  broad,  shallow  pits  ap- 


FIG.  24. —  Front  and  side  views  of  Algoma,  a  peltoid  or  shield-shaped  meteorite. 
An  iron  meteorite.     Weight,  9  pounds. 

pear  but  the  ridge-like  markings  of  the  front  side  are  entirely 
absent. 

Somewhat  similar  in  form  to  the  shield-shaped  or  peltoid 
meteorites  are  the  shell-shaped  or  ostracoid  meteorites  but 
the  origin  of  the  ostracoid  form  is  probably  quite  different 
from  that  of  the  peltoid  form.  Ostracoid  meteorites  are 
thin  and  extended,  concave  on  one  side  and  convex  on  the 
other,  with  much  more  marked  curving  than  in  the  peltoid 
meteorites.  Instead  of  owing  their  form  chiefly  to  atmos- 


70  METEORITES 

pheric  shaping,  the  ostracoid  meteorites  are  probably  pri- 
marily shaped  as  a  scaling  from  some  larger  body.  Many 
of  the  Canyon  Diablo  meteorites  showthis  shape  to  a  marked 
degree.  The  best  illustration  among  stone  meteorites  is 
Butsura,  which  fell  in  several  pieces  which,  when  put  to- 
gether, made  a  well-marked  shell  shape.  Such  a  shape  is  ill 
adapted  to  withstand  atmospheric  resistance,  and  hence  rup- 
ture of  the  individual  is  likely  to  occur. 

If  the  apex  of  the  cone  be  raised,  and  the  side  slope  be 
concave,  a  bell-shape  or  codonoid  form  will  be  produced,  of 
which  several  meteorites  afford  illustrations.  One  of  the 
best  shaped  of  these  is  the  Durala  meteorite.  The  height 
of  this  meteorite  is  7  inches;  the  diameter  of  its  base  10 
inches.  The  outline  of  the  base  is  triangular  rather  than 
circular,  but  the  angles  of  the  triangle  are  considerably 
rounded.  The  surface  of  this  meteorite  is  almost  uniformly 
smooth  and  shows  little  or  no  contrast  in  appearance  be- 
tween front  and  rear  sides. 

By  being  elongated  still  more  in  the  direction  at  right 
angles  to  its  circular  outline  the  bell-shaped  or  codonoid 
form  passes  into  the  pear-shaped  or  onchnoid  form.  Only 
iron  meteorites,  so  far  as  known,  exhibit  this  shape.  Among 
these  Boogaldi  and  Charlotte  furnish  excellent  examples, 
(Fig.  25).  In  meteorites  of  this  shape  the  orientation 
changes.  The  large,  heavy,  blunt  end  is  now  foremost,  the 
small,  pointed  end  at  the  rear.  That  such  is  the  position  of 
these  meteorites  in  falling  is  shown  beyond  a  doubt  by  the 
markings  on  Boogaldi.  At  the  thick,  heavy  end  of  this 
meteorite,  well-defined  concentric  zones  of  fused  oxides  may 
be  seen,  with  transverse  furrows  running  in  the  direction 
of  the  thinner  end  of  the  meteorite.  The  disappearance 
of  both  zones  and  furrows  is  gradual  and  in  the  same  direc- 
tion (Fig.  26).  Liversidge*  regards  these  zones  of  oxides  as 
thrown  up  by  the  resistance  of  the  air  "just  as  waves  are 
formed  in  water  or  sand  by  the  wind  or  at  the  bows  of  a 
boat."  At  the  small  end  of  the  meteorite  longitudinal 
ridges  and  furrows  may  also  be  seen  in  a  "skin"  of  fused 
oxides.  These  have  the  same  direction  as  the  furrows  at 

*Proc.  Roy.  Soc.  N.  S.  Wales,  1902,  26,  343. 


FORMS   OF   METEORITES 


71 


the  larger  end,  an'd  there  are  remains  of  drops  where  the 
melted  material  dripped  off  at  the  small  end.  Another 
indication  that  the  meteorite  moved  large  end  foremost, 
although  this  evidence  is  not  always  conclusive,  lies  in  the 
fact  that  it  was  resting  on  this  end  when  found.  The  length 
of  the  meteorite  is  5  inches  and  its  diameter  at  the  large  end 


FIG.  25. —  Onchnoid  or  pear-shaped  meteorites.  Charlotte  at  the  left,  Boogaldi 
(from  a  cast)  at  the  right.  Both  are  iron  meteorites.  Charlotte  weighed  9 
pounds;  Boogaldi,  5  pounds. 

3  inches.  The  surface  in  general  is  smooth  and  shows  no 
pittings  except  for  the  furrows  referred  to.  The  continuity 
of  the  etching  figures  to  the  edges  of  the  meteorite  as  seen  in 
section  (Fig.  27)  shows  that  the  form  of  the  meteorite  is  due 
to  erosion. 

The  Charlotte  meteorite  is  about  the  size  and  shape  of 
Boogaldi,  but  somewhat  more  flattened  laterally,  and  one 
side  is  concave.  No  markings  such  as  those  which  so  dis- 


72 


METEORITES 


FIG  26.— Forward  end  of  the  Boogaldi  meteorite  showing  waves  and  ridges 
formed  on  its  surface  by  fusion  during  its  fall.  Enlarged  1.7  diameters.  After 
Liversidge. 


\ 


Fig.  27. —  Etched  section  of  the  Boogaldi  meteorite.  The  continuity  of  the 
etching  figures  to  the  edges  of  the  mass  shows  that  the  form  of  the  mete- 
orite has  been  produced  by  erosion.  Enlarged  1.3  diameters.  After 
Liversidge. 


74       .  METEORITES 

tinctly  orient  the  Boogaldi  meteorite  seem  to  have  been 
observed  upon  Charlotte,  but  it  is  highly  probable  that  its 
position  in  falling  was  likewise  with  the  large  end  foremost. 
If  the  meteorite  is  still  more  elongated  and  acquires  a 
somewhat  convex  instead  of  a  concave  curve  in  the  direc- 
tion of  its  length,  a  column-shaped  or  styloid  form  like  that 
of  the  Babb's  Mill  meteorite  (Fig.  28)  will  be  produced. 
The  length  of  this  meteorite  is  3  feet;  breadth  10  inches, 
and  thickness  6  inches.  It  weighed  290  pounds.  It  was 
thought  by  Blake,  who  originally  described  it,  that  this 


FIG.  28. —  Babb's  Mill.     A  styloid  or  column-shaped  meteorite.     Length,  3  feet. 

Weight,  290  Ibs. 

meteorite  was  a  residual  nodule  of  an  irregularly  shaped 
mass  from  which  the  irregular  portions  had  been  thrown  off 
by  terrestrial  weathering,  but  it  seems  quite  as  likely  that 
the  form  was  acquired  in  falling. 

Of  ring-shaped  or  cricoid  forms  among  meteorites  but  a 
single  example  seems  to  be  known,  that  of  Tucson  (Fig.  29). 
This  meteorite  is  in  the  form  of  a  metallic  ring,  the  exterior 
diameter  of  which  varies  from  49  to  38  inches  and  the 
interior  diameter  from  26^  to  23  inches.  The  width  of  the 
thickest  part  of  the  ring  is  17^  inches  and  of  its  narrowest 
part  2^  inches.  The  greatest  thickness  at  right  angles  to 
the  plane  of  the  ring  is  10  inches.  It  will  thus  be  seen  that 
the  ring  is  somewhat  irregular  in  form,  but  a  general  ring 
shape  is  well  exhibited.  There  are  no  oriented  pittings 
upon  the  ring.  As  to  the  origin  of  this  ring,  opinions  differ. 
Haidinger  concluded*  that  the  meteorite  rotated  in  its 

*Sitzb.  Wien.  Akad.,  1870,  Bd.  61,  II,  p.  506-511. 


FORMS   OF   METEORITES  75 

descent  and  that  thus  a  hole  was  bored  through  it  by  the 
air.  Observation  of  the  action  of  the  air  upon  other  meteo- 
rites does  not  confirm  this  view,  however.  It  is  more  prob- 
able that  the  ring  existed  preterrestrially  as  a  portion  of  an 
otherwise  stony  mass  and  that  the  stony  portion  fused  or 
fell  away  in  the  passage  of  the  mass  to  the  earth.  This 
view  is  rendered  somewhat  more  probable  by  the  fact  that 
the  iron  contains  about  five  per  cent  of  silicates. 


FIG.  29. —  A  cricoid  or  ring-shaped  meteorite.     One  of  the  Tucson,  Arizona,  fall. 
It  is  an  iron  meteorite  and  weighs  1514  IBs. 

Of  jaw-sKaped  or  gnathoid  meteorites  Kokstad  and  Hex 
,River  (Fig.  30)  furnish  excellent  examples.  These  are  both 
iron  meteorites  and  of  nearly  the  same  size.  Kokstad  is  26 
inches  long,  12  inches  wide  at  the  angle  of  the  "jaw,"  and 
3  inches  thick.  Its  surface  is  comparatively  smooth  except 
for  one  large  circular  depression  probably  caused  by  the 
fusing  out  of  a  troilite  nodule.  Hex  River  is  20  inches  long, 
II  inches  wide,  and  7  inches  thick.  It  is  thus  somewhat 


76 


METEORITES 


more  massive  than  Kokstad  and  approximates  the  pear 
shape.  Unlike  Kokstad,  it  is  deeply  pitted  all  over  its 
surface.  The  pits  are  broad,  shallow  depressions  of  rather 
uniform  size,  in  part  so  arranged  as  to  give  the  impression 
of  furrows  passing  around  the  "jaw"  at  right  angles  to  its 
length.  Nothing  in  the  distribution,  size,  or  shape  of  the 
pittings  seems  to  give  a  clue  as  to  the  position  of  the  mete- 
orite in  falling.  From  its  resemblance  in  form  to  the  pear- 
shaped  meteorites,  however,  it  may  be  surmised  that  it 


FIG.  30. —  Gnathoid   or  jaw-shaped   meteorites.     Upper  one,   Hex   River;  lower, 
Kokstad.     Both  are  iron  meteorites  and  weiirh  about  100  pounds  each. 

fell  with  the  heavy  end  foremost.  The  jaw  shape  is  ex- 
hibited in  some  degree  also  by  the  great  Bacubirito  mete- 
orite, (Frontispiece)  although  the  form  is  not  as  well  marked 
as  in  those  previously  described.  The  surface  of  this  mete- 
orite is  quite  uniformly  covered  with  pittings,  regular  in  size, 
2  to  3  inches  in  diameter,  with  well-defined  walls  and  quite 
shallow.  No  characters  seem  to  afford  data  for  an  orienta- 
tion of  the  mass.  A  single,  small  specimen  of  Toluca  in 
the  Field  Museum  collection  also  exhibits  a  gnathoid  shape. 
It  is  reasonable  to  suppose  that  this  shape  would  be  exhib- 


FORMS   OF   METEORITES  77 

ited  only  by  iron  meteorites,  since  stone  meteorites  if  of  this 
form  would  be  likely  to  be  broken  up  in  passing  through 
the  earth's  atmosphere.  The  most  satisfactory  suggestion 
that  seems  to  have  been  made  regarding  the  origin  of  the 
gnathoid  shape  is  that  of  Brezina,*  who  thought  that  it  arose 
from  the  breaking  apart  of  a  ring  like  that  of  Tucson.  It 
is  clear  that  such  forms  might  arise  from  a  dismembered 
ring,  but  whether  this  was  the  actual  origin  of  those  known 
cannot,  of  course,  be  stated  positively. 

The  other  meteorite  forms  mentioned,  such  as  cuboidal, 
pyramidal,  tetrahedral,  etc.,  are  exhibited  by  various 
meteorites  and  especially  those  falling  in  showers.  Here  the 
action  of  the  air  has  frequently  not  been  sufficient  to  greatly 
modify  the  original  angular  form,  and  hence  such  forms  as 
would  be  found  in  freshly  broken  terrestrial  rocks  occur. 

*Verh.  der  K.  K.  geolog.  Reichsanstalt,  Wien,  1887,  289. 


CHAPTER  VIII 

CRUST   OF   METEORITES 

All  meteorites  are  characterized  by  a  more  or  less 
smoothed  or  rounded  coating  differing  in  color  or  texture 
or  both  from  that  of  the  substance  of  the  meteorite  beneath. 
This  superficial  skin  or  coating  is  known  as  the  "crust"  and 
is  a  distinguishing  character  of  meteorites.  It  is  obviously 
the  result  of  fusion  of  the  surface  of  the  meteorite  by  heat 
encountered  during  the  passage  of  the  mass  through  the 
atmosphere.  Being  the  result  of  fusion,  it  varies  according 
to  the  constitution  of  the  meteorite.  If  the  meteorite  is 
composed  of  feldspar  and  augite,  for  example,  which  are 
minerals  fusible  with  comparative  ease,  a  smooth  and 
varnish-like  crust  flowing  in  little  rivulets  over  the  surface 
is  seen.  If,  however,  the  meteorite  is  composed  chiefly  of 
the  difficultly  fusible  minerals,  bronzite  and  chrysolite,  as 
are  the  majority  of  stone  meteorites,  a  rough,  scoriaceous 
crust  is  formed.  The  color  of  the  crust  also  varies  with 
the  composition  of  the  meteorite.  Meteorites  containing 
iron  compounds  in  even  small  quantity  have  a  black  or 
dark-colored  crust  on  account  of  the  presence  of  these  sub- 
stances. If,  however,  iron  compounds  are  lacking,  the  crust 
may  be  nearly  colorless  as  in  the  meteorite  of  Bishopville, 
or  yellowish,  as  in  Bustee.  Inasmuch  as  iron  or  its  com- 
pounds is  a  nearly  constant  component  of  meteorites,  a 
black  or  dark  crust  is  to  be  found  on  the  majority  of  them. 
Since  iron  meteorites  consist  almost  wholly  of  iron,  the  crust 
upon  them  is  usually  black  when  they  are  freshly  fallen. 
Iron  meteorites  are,  however,  not  as  uniformly  or  plainly 
encrusted  as  are  the  stone  meteorites.  The  crust  of  iron 
meteorites  when  it  can  be  separated  is  found  to  have  the 
composition  of  magnetite.  It  is  usually  very  thin  (i  mm. 
and  less)  and  dull  or  only  weakly  shining.  Its  surface  may 
be  smooth  or  rough,  shagreened  or  warty,  and  occasionally 

78 


CRUST  OF   METEORITES 


79 


slaggy.  Reichenbach  called  it  "iron  glass"  (Eisenglas),  but 
the  term  is  hardly  an  apt  one,  since,  as  Cohen  remarks,  the 
substance  is  not  iron  and  not  glass.  In  addition  to  the 
formation  of  crust,  there  is  an  alteration  by  heat  of  the 
periphery  of  iron  meteorites  producing  a  zone  exhibiting 
a  granular  structure  which  may  be  seen  about  the  edge  of 
the  meteorite.  It  is  illustrated  in  the  accompanying  figure 


I 


FIG.  31. —  Heat  crust  of  Charlotte  meteorite.  The  heating 
of  the  surface  in  the  passage  of  the  meteorite  to  the  earth 
produced  the  granular  edge  seen  at  the  left.  X2.£. 

of  a  section  of  the  Charlotte  meteorite,  (Fig.  31).  This 
zone  varies  in  width  from  an  extreme  of  10  mm.  in  Cabin 
Creek  to  less  than  I  mm.  in  Prambanan.  As  a  rule,  the 
zone  is  thinner  the  greater  the  weight  of  the  meteorite, 
although  there  are  some  exceptions  to  this.  Such  a  rela- 
tion of  the  width  of  the  zone  to  the  weight  of  the  meteorite 
is  doubtless  due  to  the  greater  difficulty  of  heating  the 
larger  masses.  Since  most  iron  meteorites  have  not  been 


80 


METEORITES 


found  until  some  time  after  their  fall,  they  have  generally 
suffered  oxidation  which  has  considerably  altered  if  it  has 
not  altogether  destroyed  their  fusion  crust.  In  its  place 
one  finds,  as  a  rule,  an  oxidized  crust,  usually  of  a  reddish 
brown  color  and  of  varying  thickness.  The  rapidity  with 
which  it  may  form  is  largely  dependent  on  the  constitution 
of  the  meteorite,  those  having  considerable  chlorine  oxidizing 


FIG.  32. —  Surface  relief  of  Juncal  meteorite  produced  by  terrestrial  erosion. 

the  most  rapidly.  Climate  is  also  an  important  factor  in 
determining  the  rate  of  oxidation  of  iron  meteorites.  De- 
composition takes  place  much  more  rapidly  in  wet  than 
in  dry  climates. 

The  erosion  of  dry  climates  sometimes  produces  peculiar 
markings  on  the  surface  of  iron  meteorites.  These  markings 
may  simply  be  numerous,  small,  circular  pits  independent 
of  one  another  or  they  may  run  together  to  produce  rills  like 
those  seen  on  the  surface  of  the  Juncal  meteorite  (Fig.  32). 
The  position  of  these  rills  coincides  with  the  lamellar  struc- 
ture of  the  meteorite.  Such  an  appearance  is  especially 


CRUST   OF   METEORITES  81 

characteristic  of  the  meteorites  which  have  been  obtained 
from  the  Chilean  desert,  but  it  is  also  shown  on  the  Austra- 
lian meteorite  of  Youndegin. 

In  both  stone  and  iron  meteorites  the  thickness  and  other 
characters  of  the  crust  vary  in  different  parts  of  the  mete- 
orite. Many  of  the  characters  depend  on  the  position  of 
the  meteorite  in  its  flight  through  the  atmosphere  and  the 
length  of  time  during  which  the  different  surfaces  have  been 
exposed.  On  the  side  of  the  meteorite  which  was  in  front 
in  its  course  the  crust  is  thinner  and  shows  more  complete 
fusion  than  on  the  side  which  was  behind.  Other  portions 
of  the  meteorite  may  show  a  thickened  crust  from  the  flow 
of  fused  matter  to  those  points.  A  feature  occasionally 
seen  in  the  crust  of  some  stone  meteorites  is  a  marking  off 
by  fissures  into  little  angular  fields  such  as  are  seen  on 
"crackled"  earthenware.  These  are  evidently  due  to  con- 
traction in  the  cooling  of  the  crust.  In  contrast  to  the 
generally  rough  appearance  of  the  crust  of  some  stone 
meteorites,  there  occur  in  places  spots  which  appear  to  have 
been  glazed  over.  These  are  generally  round  or  oval,  from 
2  to  10  mm.  in  diameter,  smooth  and  usually  of  a  yellowish 
or  reddish  color  as  compared  witb  the  black  crust.  They 
appear  to  represent  the  location  of  exceptionally  fusible  con- 
stituents upon  the  surface  of  the  meteorite.  They  are 
quite  characteristic  of  the  stones  of  Mocs,  also  are  seen  in 
some  of  those  of  Modoc,  L'Aigle,  etc.  Where  nickel-iron 
appears  upon  the  surface  of  stone  meteorites  it  generally 
projects  in  rounded  forms,  especially  if  the  grains  are  large. 
This  indicates  that  it  is  more  refractory  than  the  siliceous 
constituents  of  the  meteorites.  In  other  cases,  however, 
the  nickel-iron  may  oxidize  sufficiently  to  form  with  the 
silicates  a  more  fusible  compound  and  cause  pits  instead  of 
knobs.  The  thickness  of  the  crust  of  the  stone  meteorites 
depends  somewhat  upon  their  texture,  a  compact  stone 
having  a  thinner  crust  than  one  of  more  open  texture. 
Upon  meteorites  of  a  relatively  porous  character  the  crust 
may  reach  a  thickness  of  10  mm.,  though  a  lesser  thickness 
is  usual.  The  stones  of  the  meteoric  shower  of  Mocs  fur- 
nish proof  that  in  the  stone  meteorites  the  thickness  of  the 


82 


METEORITES 


crust  does  not  vary  with  the  size  of  the  stone.  Though  the 
stones  were  of  many  sizes,  the  thickness  of  the  crust  was 
invariably  ^3  to  ^  mm.  All  of  these  features  indicate 
that  the  crust  is  the  result  of  a  sudden,  brief  heating. 

When  seen  under  the  microscope  in  section,  the  crust  of 
most  stone  meteorites  presents  the  interesting  feature  of 
three,  and  in  some  cases  four,  well-marked  zones  (Fig.  33). 


FIG.  33. —  Microscopic  section  of  a  Mocs  meteorite  showing  (above) 
three  zones  of  the  crust.     X  70. 

The  outermost  of  these,  called  the  fusion  zone,  is  thin  as 
compared  with  the  other  two,  glassy,  black  and  opaque  to 
brown  and  transparent.  Beneath  it  lies  a  broader,  trans- 
parent zone  in  which  the  constituents  of  the  meteorite  ap- 
pear little,  if  any,  changed.  This  was  called  by  Tschermak 
the  absorption  zone  (Saugzone).  Next  and  last  follows  a 
broad  zone  of  black,  opaque,  spotted  appearance.  This 
zone  may  be  so  broad  as  to  make  up  four-fifths  of  the  width 


CRUST   OF   METEORITES  83 

of  the  crust.  The  constituents  of  the  meteorite  appear  in 
this  portion  of  the  crust  to  be  in  normal  condition,  but 
impregnated  with  black,  generally  opaque  matter.  Hence 
this  zone  was  called  by  Tschermak  the  impregnation  zone 
(Impragnationszone).  The  relative  width  of  the  three  zones 
was  found  by  Ramsay  in  Bjurbole  to  be  as  follows:  Outer 
zone,  o.i  mm.;  middle  zone,  0.2  mm.;  inner  zone,  0.3  mm. 
The  relative  and  total  widths  of  these  zones  vary  in  differ- 
ent meteorites,  being  usually  the  broadest  in  the  more  fri- 
able and  porous  meteorites.  In  compact  meteorites  the 
crust  is  thinner,  and  often  only  the  outer,  fused  zone  can 
be  distinguished.  In  the  crust  of  other  meteorites  again 
the  middle,  transparent  zone  may  be  lacking  and  only  the 
opaque,  outer  and  inner  zones  be  seen.  On  many  of  the 
stones  of  Mocs,  Brezina  noted  a  very  thin  layer  of  yellow 
transparent  substance  outside  of  the  fusion  zone,  so  that 
the  number  of  zones  was  raised  to  four. 

The  origin  of  the  three  crust  zones  seems  best  accounted 
for  by  the  theory  of  Tschermak  that  fused  matter  from  the 
exterior  penetrates  through  the  middle  zone  and  congeals 
in  the  inner  zone. 

In  the  crust  of  the  St.  Michel  meteorite  Borgstrom* 
found  a  large  excess  of  pyrrhotite  in  the  inner  or  impregna- 
tion zone.  As  pyrrhotite  is  the  most  fusible  ingredient  of 
this  as  well  as  of  all  meteorites,  he  urged  that  the  opacity  of 
the  impregnation  zone  was  probably  due  to  the  chilling  and 
collecting  there  of  pyrrhotite  which  had  flowed  inward 
from  the  outer  crust  in  a  fused  condition.  From  the  fusing 
temperature  of  pyrrhotite  Prof.  Sundell  calculated  the  length 
of  time  during  which  the  crust  had  been  exposed  to  heat,  or 
in  other  words  the  time  of  formation  of  the  crust  to  be  1.16 
seconds. 

Between  a  completely  developed  crust  and  no  crust  at 
all,  various  gradations  occur  according  to  the  length  of  time 
during  which  a  meteoritic  surface  is  exposed  during  the  flight 
of  the  meteorite  through  the  atmosphere.  As  meteoritic  in- 
dividuals often  break  up  during  their  flight  to  the  earth, 
different  surfaces  will  be  exposed  for  varying  lengths  of 

*Bull.  Com.  Geol.  de  Finlande,  1912,  34,  22. 


84  METEORITES 

time.  Those  which  become  exposed  just  before  reaching 
the  earth  will  have  no  crust  at  all;  those  exposed  a  little 
longer  will  appear  as  if  smoked.  A  little  longer  exposure 
may  produce  a  blackening  of  the  entire  surface,  but  without 
glazing  or  smoothing,  and  between  this  and  a  well-formed 
crust  all  gradations  may  occur.  Such  a  partial  encrusting 
is  often  called  a  secondary  crust  to  distinguish  it  from  the 
well-formed  primary  crust.  Individuals  of  a  meteoritic 
shower  frequently  exhibit  several  grades  of  secondary  crust, 
due  to  successive  disruptions  in  the  air. 


CHAPTER  IX 

VEINS  OF  METEORITES 

Many  of  the  stony  meteorites  are  penetrated  by  black, 
thread-like  veins.  These  veins  may  run  continuously  or 
with  interruptions,  and  may  be  close  together  or  scattered. 
When  very  numerous  they  give  to  the  meteorite  a  brecciated 
appearance  and  may  be  so  abundant  as  to  color  the  whole 
mass.  They  seem  to  be  largely  confined  to  the  chondritic 
meteorites,  being  seen  among  the  achondrites  only  in  Bish- 
opville.  So  abundant  are  they  among  the  chondrites  that 
Brezina  made  the  presence  of  veins  a  ground  of  subdivision 
of  all  their  groups.  Of  267  chondrites  he  reported  145  either 
veined  or  breccia-like.  The  white  and  intermediate  chon- 
drites showed  the  largest  per  cent  of  veining,  and  the  gray 
chondrites  the  largest  amount  of  breccia-like  structure.  In 
the  spherical  and  crystalline  chondrites  both  features  were 
less  frequently  observed. 

The  course  of  the  veins  is  not  as  a  rule  marked  by  any 
particular  system  or  direction.  It  is  generally  more  nearly 
straight  than  curved,  but  there  may  be  much  forking  and 
anastomosing.  In  the  Bluff  meteorite  two  systems  of  veins 
cross  at  angles  of  about  45°.  The  narrower  of  these  veins 
is  of  nearly  uniform  width  and  was  observed  over  a  plane 
4x15  inches.  The  other  vein  varies  in  width  and  is  less  ex- 
tensive. Some  veins  are  so  delicate  as  to  appear  in  section 
like  the  finest  hair,  scarcely  o.oi  mm.  in  thickness.  On  the 
average  they  have  a  thickness  of  about  o.i  mm.  The  thick- 
ness as  a  rule  is  pretty  uniform,  but  swellings  and  knottings 
may  appear.  Sometimes  vein-like  masses  are  seen  more 
than  an  inch  in  thickness,  and  single  stones  of  Pultusk  and 
Mocs  seem  to  be  made  up  wholly  of  vein  material.  Other 
meteorites  showing  large  vein  masses  are  Chantonnay, 
L'Aigle,  Orvinio,  and  Stalldalen.  Another  feature  allied  to 
veins  seen  in  many  meteorites  (best  disclosed  on  breaking 

85 


86 


METEORITES 


the  stone)  is  that  of  smoothed,  blackened  surfaces  passing 
in  various  directions.  They  are  termed  armored  surfaces 
(H^rnischflache).  Such  surfaces  have  been  likened  to  the 
slickensides  of  terrestrial  rocks,  also  to  stylolites.  They 
pass  to  veins  by  insensible  gradations. 


FIG.  34. —  Cross  section  of  a  vein  of  one  of  the  Mocs  meteorites.  The  vein 
mass  appears  as  a  broad  black  band  through  the  center.  It  is  in  part 
intermixed  with  the  adjoining  ground  mass  and  in  part  has  well-defined 
walls.  The  gray  spots  are  lumps  and  spheres  of  nickel-iron  illuminated 
by  reflected  light.  The  branching  of  some  of  these  into  clefts,  one  of 
which  is  still  open,  is  of  interest.  X2O.  After  Tschermak. 

Under  the  microscope  the  principal  substance  of  the  black 
veins  appears  like  that  of  the  first  and  third  layers  of  the 
crust.  It  is  opaque,  dull,  half  glassy,  showing  in  reflected 
light  fused  spheres  of  nickel-iron  and  pyrrhotite  and  grains 
of  nickel-iron  branching  out  into  delicate  leaves  (Fig.  34). 


VEINS   OF   METEORITES  87 

The  occurrence  of  these  fine  iron  veins  furnishes  the  chief 
distinction  between  the  substance  of  the  crust  and  that  of 
the  black  veins.  The  boundary  between  the  veins  and  the 
adjoining  stone  is  at  times  sharp  and  again  gradual.  In 
the  latter  case  the  ground  mass  seems  to  be  impregnated 
by  a  black,  half-glassy  injection.  In  the  broader  veins  a 
distinct  flow  structure  of  the  substance  is  evident.  The 
finer  veins  in  their  course  tend  to  avoid  the  chondri  and 
follow  the  pyrrhotite. 

In  three  meteorites  analyses  of  the  normal  stone  and  of 
the  vein  substance  have  been  made.  These  meteorites  are 
Orvinio,  Stalldalen,  and  Bluff.  The  analysis  of  the  nor- 
mal stone  is  shown  in  the  following  table  in  each  case  under 
a,  that  of  the  vein  under  b. 

ANALYSES  OF  VEIN  MATERIAL 

a  b  a  b  a  b 

Si02 38.01         36.82  35.71          38.32  37.70         38.96 

A12O3 2.22  2.31  2.11  2.15  2.17  1.89 

FeO 6.55  9.41  10.29  9.75  23.82  22.98 

MgO 24.11  21.69  23.16  25.01  25.94  7-52 

CaO 2.33  2.31  1.61  1.84  -2.20  tr. 

Na2O 1.46  0.96'                ....  

K2O 0.31  o .  26               '        

MnO ....  ....  0.25  i.oo  ....  .... 

NiO ....  0.20  0.42                 '  

Fe 22.34  22-H  21.10  17.47  4-4i  2.30 

Ni+Co 2.15  3.04  1.78  1.02  1.75  3.26 

1.94  2.04  2.27  2.51  1.30  0.26 

P2O5 0.30  0.31                 

101.42       100.95  98-78         99-8o  99.29         97.17 

G= 3-675        3-6oo  3.733        3.745  3.510        3.585 


REFERENCES 

1.  Orvinio.  Sipocz.  Sitzb.  Wien  Akad,  1874,  70,  i,  464. 

2.  Stalldalen.  Lindstrom.  Geo!.  Foren.  Stockholm,  1878,  4,  53-54. 

3.  Bluff.  Whitfield  and  Merrill.     Am.  Jour.  S.ci.,  1888,  3,  36,  119. 

These  analyses  make  it  evident  that  the  substance  of 
the  veins  does  not  differ  essentially  from  that  of  the  mete- 
orite. The  vein  matter,  therefore,  has  doubtless  been 
formed  by  alteration  in  place  of  the  substance  of  the  mete- 
orite and  does  not  represent  foreign  matter  introduced  into 
a  fissure,  as  is  the  case  with  most  veins  in  terrestrial  rocks. 
For  this  reason,  therefore,  the  term  veins  applied  to  these 


88  METEORITES 

formations  in  meteorites  is  somewhat  misleading,  and  the 
lack  of  analogy  to  veins  in  terrestrial  rocks  should  be  kept 
in  mind. 

The  similarity  in  composition  between  the  vein  and  the 
substance  of  meteorites  and  the  resemblance  of  the  vein 
matter  to  the  crust  seem  to  make  clear  the  origin  of  the 
veins.  They  are  apparently  produced  by  the  penetration 
of  heat  into  the  fissures  of  the  meteorite  during  its  passage 
through  the  atmosphere.  Some  have  thought  that  the  vein 
matter  was  fused  matter  from  the  surface  which  flowed 
into  fissures;  but,  as  Tschermak  pointed  out,  the  low  tem- 
perature of  the  interior  of  the  meteorite  would  probably 
prevent  this.  In  Chantonnay  he  found  several  fissures  into 
which  the  fused  matter  from  the  surface  had  penetrated  to 
a  depth  of  but  6  mm.,  leaving  the  fissure  open  for  the  re- 
mainder of  its  course.  Earlier  writers  were  inclined  to  re- 
gard the  veins  of  preterrestrial  origin,  but  there  seems  no 
need  to  assume  this.  Reichenbach  regarded  some  veins  of 
cosmic,  others  of  telluric,  origin.  The  cosmic  veins,  he 
stated,  avoided  the  larger  constituents  of  the  meteorites 
and  characterized  the  iron-rich,  dark,  and  compact  chon- 
drites.  The  telluric  veins  passed  through  the  larger  constit- 
uents and  characterized  the  light,  iron-poor  chondrites. 
These  distinctions  have  not  been  accepted  by  later  ob- 
servers. That  the  substance  of  the  chondrites  turns  black 
upon  heating  has  been  abundantly  proved  experimentally. 
Meunier  observed  that  a  piece  of  Pultusk  became  black 
upon  heating  it  in  a  stream  of  carbonic  acid  gas.  A  piece 
of  Tadjera  was  turned  red  by  heating  in  a  current  of  air 
and  later  black  by  heating  in  hydrogen  or  carbonic  acid  gas. 
Cohen,  heating  pieces  of  Lancon  in  a  platinum  boat  to  a 
point  at  which  hard  glass  softened,  obtained  only  a  reddish 
brown  color  both  in  a  current  of  air  and  in  one  of  hydrogen; 
but  on  heating  in  the  flame  of  a  blast  lamp  in  a  platinum 
crucible,  a  black  color  appeared.  He,  therefore,  concluded 
that  the  amount  of  heat  rather  than  the  presence  or  ab- 
sence of  oxygen  caused  the  production  of  the  black  color. 
Besides  black  veins,  metallic  veins  consisting  largely  of 
nickel-iron  occur  in  some  meteorites,  especially  in  Farming- 


VEINS   OF   METEORITES  89 

ton  and  Tabory.  The  form  and  distribution  of  these 
metallic  veins  seem  to  be  similar  to  that  of  the  black  veins, 
and  it  is  the  belief  of  Cohen  *  that  all  gradations  occur 
between  the  two  kinds.  The  broad,  black  veins  often  have 
more  or  less  metallic  interiors  and  an  increase  of  this  metal- 
lic substance  would  produce  a  metallic  vein.  The  present 
writer,  has  however,  f  called  attention  to  the  fact  that  a 
diminution  of  the  metallic  substance  of  an  iron-stone  mete- 
orite might  equally  well  produce  the  veins.  Perhaps  both 
methods  of  origin  are  possible.  In  the  Farmington  mete- 
orite, which  is  the  one  in  which  the  metallic  veins  are  best 
developed,  the  veins  penetrate  throughout  the  mass,  and  it 
is  not  easy  to  understand  how  a  substance  so  difficultly 
fusible  as  nickel-iron  could  be  so  distributed  by  the  pene- 
tration of  heat  into  the  fissures. 

Black  veins  also  occur  in  iron  meteorites,  penetrating 
between  the  bands  and  at  times  crossing  their  course. 
Their  usual  contour  has  been  accurately  described  by  Cohen 
as  like  that  of  a  stroke  of  lightning.  The  substance  of  these 
veins  where  it  has  not  suffered  terrestrial  alteration  is  hard, 
takes  a  good  polish,  and  resists  acid.  It  was  regarded  by 
Reichenbach  and  Brezina  as  magnetite  and  as  probably  pro- 
duced by  the  penetration  of  heat  and  air  into  the  fissures  of 
the  meteorite.  In  the  view  of  the  present  writer,  a  fissuring 
of  iron  meteorites  can  take  place  after  their  fall  by  the 
penetration  of  slow  oxidation  inward,  which  would  give  a 
vein-like  appearance.  The  alteration  of  a  magnetite  vein 
to  limonite  might  also  produce  such  an  effect.  Structures 
similar  to  the  armor  faces  of  stone  meteorites  have  been 
noted  in  the  iron  meteorites  of  Quesa  and  Sacramento. 

Probably  related  to  armored  surfaces  (page  86)  are  the 
slickensides  seen  in  some  stone  meteorites,  notably  Long 
Island  (Fig.  35).  These  in  Long  Island  lack  the  dark  color, 
as  if  rubbed  with  graphite,  which  is  common  to  the  average 
armored  surface.  They  are  smooth,  shining,  somewhat  un- 
even, and  striated  in  the  direction  of  movement.  The  sur- 
faces may  be  parallel  to  each  other  at  different  levels  and 

*Meteoritenkunde,  Heft  II,  p.  121. 
fAm.  Jour.  Sci.,  1901,  4,  n,  60-62. 


90 


METEORITES 


also  run  in  different  directions.  In  Long  Island  three  of 
these  directions  are  nearly  at  right  angles  to  one  another. 
The  movement  has  brightened  and  elongated  the  metallic 
grains,  but  produced  no  other  changes  in  the  immediately 
adjoining  areas.  Cohen  has  urged  that  these  surfaces  are 


FIG.  35. —  Slickensided  surface,  Long  Island  meteorite.     Natural  size. 

terrestrial  in  origin,  but  this  seems  to  the  author  unlikely. 
Their  coursing  in  different  directions  makes  it  difficult  to 
ascribe  them  to  impact  upon  the  earth,  as  was  done  by 
Cohen,  as  in  such  case  the  movement  would  be  expected  to 
be  in  a  single  direction. 

In  iron  meteorites  evidence  of  internal  movement  is 
afforded  by  faulting  in  the  etching  figures.  Bridgewater, 
Carlton,  Descubridora,  Magura,  and  Puquios  are  meteorites 


VEINS   OF   METEORITES  91 

in  which  such  faults  have  been  described.  In  Puquios 
dislocation  has  taken  place  in  several  directions.  The 
largest  fault  extends  the  entire  length  of  the  mass  and  has  a 
throw  of  3  mm.  In  Descubridora  a  throw  of  from  6  to  12 
mm.  has  been  noted.  The  faulting  is  believed  by  Brezina 
to  be  due  to  the  impact  of  the  meteorite  on  the  earth, 
though  Howell  was  inclined  to  ascribe  it,  in  the  case  of  the 
Puquios  meteorite  at  least,  to  the  passage  of  the  mass  near 
the  sun,  causing  high  heating. 

Another  evidence  of  movement  in  iron  meteorites'  is 
afforded  by  bent  or  curved  figures  such  as  have  been  noted 
in  Bacubirito,  Carlton,  Glorieta,  Jamestown,  and  Toluca. 
Such  figures  are  usually  confined  to  a  small  area  on  a 
single  meteorite  and  are  probably  correctly  assumed  to  be 
produced  by  the  impact  of  the  meteorite  on  the  earth. 
The  writer  has  produced  them  by  boring  or  hammering  a 
meteorite. 


CHAPTER   X 

STRUCTURE  OF  METEORITES 

STRUCTURE  OF  IRON  METEORITES 

Iron  meteorites  as  seen  upon  a  polished  surface  usually 
present  a  homogeneous  and  uniform  structure.  Some- 
times cleavage  planes  of  considerable  dimensions  pass 
through  individual  masses,  and  broken  fragments  of  iron 
meteorites  often  exhibit  a  hackly  surface  or  various  small 
cleavage  planes.  Large  structural  peculiarities  are,  how- 
ever, generally  wanting.  The  nearest  approach  to  them  is 
to  be  seen  in  the  iron  of  Mount  Joy,  which  appears  to  be 
composed  of  irregular  nodules,  some  of  which  are  an  inch 
or  two  in  length.  These  are  generally  regarded,  however, 
as  phases  of  a  crystalline  structure  on  a  large  scale.  But 
though  large  structural  features  are  wanting,  when  examined 
intimately  most  iron  meteorites  exhibit  a  well-marked 
minute  structure.  It  is  most  successfully  brought  to  view 
by  etching  a  polished  surface  of  the  meteorite.  Then  there 
appear,  on  the  majority  of  iron  meteorites,  figures  formed 
of  parallel  bands  intersecting  in  two  or  more  directions, 
(Fig.  36).  These  are  called  Widmanstatten  *  figures  after 
Alois  von  Widmanstatten  of  Vienna,  who  first  produced 
them  in  1808  by  heating  a  section  of  the  Agram  meteorite. 
The  presence  of  these  figures  shows  that  the  iron  is  in  reality 
made  up  of  a  number  of  laminae  or  plates  lying  in  parallel 
and  crystalline  positions.  Wherever  the  structure  appears 
in  this  form  it  is  found  that  the  plates  are  parallel  to  the 
four  pairs  of  faces  of  an  octahedron.  The  structure  is 
therefore  octahedral,  and  such  irons  are  known  as  octahedral 
irons.  While  the  structure  may  be  in  a  general  way  de- 
scribed as  made  up  of  plates  parallel  to  the  planes  of  an 
octahedron,  it  is  in  reality  as  a  rule  more  complex  than  this. 
Generally  each  plate  or  lamella  is  itself  made  up  of  many 

*The  word  is  sometimes  given  the  adjective  form,  Widmanstattian. 

92 


STRUCTURE   OF   METEORITES 


93 


smaller  plates  combined  in  twin  position,  arranged  accord- 
ing to  the  positions  of  twelve  faces  of  the  trisoctahedron,  112. 
These  smaller  plates  or  lamellae  repeat  the  structure  of  the 
larger  lamellae.  So  far  as  their  coarse  structure  is  con- 
cerned, the  larger  lamellae  as  seen  in  section  consist  of  a 


FIG.  36. —  Typical  octahedral  etching   figures   of  an   iron   meteorite.     The  Red 

River  meteorite. 

broad,  central  band  to  which  Reichenbach  gave  the  name 
of  kamacite,  from  /ea^a£,  a  shaft,  bounded  on  either  side 
by  a  thin  border  to  which  Reichenbach  gave  the  name 
taenite,  from  rcuvia,  a  ribbon.  Angular  interstices  between 
intersecting  lamellae  may  be  filled  with  a  homogeneous 
substance  known  as  plessite  or  partly  with  this  and  partly 
with  structures  repeating  on  a  smaller  scale  those  of  the 
larger  lamellae.  The  interstices  are  usually  known  as  fields. 


94 


METEORITES 


Various  minute  structures  may  be  scattered  through  the 
fields,  most  prominent  among  which  are  combs  (Kamme). 
These  run  out  from  the  principal  lamellae,  but  differ  from 
the  primary  lamellae  in  their  smaller  size  and  also  in  that  the 
taenite  and  kamacite  in  them  are  fused  together.  Other  in- 
clusions in  the  fields  may  be  (i)  minute  flakes  of  taenite 


FIG.  37 


FIG.  38 


FIG.  39  FIG.  40 

FIGS.  37-40. —  Four  figures  showing  how  the  etching  fig- 
ures of  an  octahedral  meteorite  will  be  affected  by  the 
direction  in  which  the  section  is  cut. 

giving  a  shimmering  appearance  and  (2)  slightly  indicated 
small  lamellae  giving  a  half-shaded  effect.  Again  small  la- 
mellae may  lie  nearly  alone  in  a  field. 

Considerable  differences  in  the  figures  of  different  mete- 
orites are  produced  by  variations  in  the  grouping,  size,  and 
shape  of  the  lamellae.  Thus  the  lamellae  may  be  in  par- 
allel groups  of  nearly  equal  length  or  they  may  be  of  un- 
equal length,  the  middle  ones  in  this  case  usually  being  the 
longer.  Again  the  lamellae  may  be  long  or  short  and  may 


STRUCTURE   OF   METEORITES  95 

be  of  uniform  width  or  have  rounded  or  irregular  outlines. 
Again,  they  may  vary  much  in  width,  extremes  of  variation 
being  from  a  fraction  of  a  millimeter  to  several  millimeters. 
Such  variations  as  are  above  described  do  not  occur  to  any 
large  extent  on  any  single  meteorite.  Almost  without  ex- 
ception, the  figures  are  uniform  throughout  any  individual 
mass  and  for  all  the  individuals  of  a  single  fall.  This  fact 
aids  in  distinguishing  meteorites  of  different  falls.  The  an- 
gles at  which  the  lamellae  intersect  in  any  given  section 
will  depend  as  shown  in  the  accompanying  figures  (Figs. 
37-40)  on  the  direction  of  the  section  with  relation  to  the 
octahedral  structure.  Thus  if  the  section  should  be  par- 
allel to  an  octahedral  face  (as  in  Fig.  37)  the  section  will 
show  three  systems  of  bands  intersecting  at  angles  of  60°. 
If  it  is  parallel  to  a  cubic  face  (Fig.  38)  it  will  show  two 
systems  of  bands  intersecting  at  angles  of  90°.  If  it  is  par- 
allel to  a  dodecahedral  face  it  will  show  two  systems  of  bands 
intersecting  at  angles  of  109°  28',  and  two  others  which  will 
bisect  this  angle  (Fig.  39).  If  it  should  be  made  in  any 
other  direction,  and  this  is  of  course  most  likely,  it  will 
show  bands  running  in  four  directions  and  intersecting  at 
unequal  angles  (Fig.  40). 

A  modification  of  the  octahedral  structure  observed  by 
Rinne*  in  a  section  of  the  Bethany  (Gibeon)  iron,  showed, 
as  may  be  seen  in  the  accompanying  figure  (Fig.  41),  in 
addition  to  the  usual  octahedral  lamellae,  lamellae  running 
parallel  to  the  planes  of  a  cube.  To  meteorites  having  this 
structure  Rinne  gave  the  name  tesseral-octahedrites.  In 
English,  the  term  tesselated  octahedrites  is  perhaps  better. 
Plates  of  pyrrhotite  found  in  this  iron  followed  the  planes 
of  the  dodecahedron  in  their  arrangement. 

Another  of  the  Bethany  (Mukerop)  irons  showed  a  struc- 
ture which  has  not  been  elsewhere  observed  which  seems  to 
be  a  mass  twinning.  The  meteoritic  individual  which  shows 
this  twinning  weighs  about  350  pounds.  It  appears  on  etch- 
ing to  be  made  up  of  three  individuals  of  about  equal  size. 
These  are  separated  as  seen  on  an  etched  plate  by  two 
straight  clefts  which  run  through  the  plate  in  parallel  direc- 

*Neues  Jahrb.,  1910,  I,  115-117. 


96  METEORITES 

tions.  These  clefts  run  parallel  to  octahedral  planes.  The 
clefts  divide  the  etched  plate  into  three  nearly  equal  parts, 
all  of  which  differ  in  their  etching  figures.  On  two  of  the 
parts  the  usual  figures  of  a  fine  octahedrite  are  shown,  but 
they  run  in  different  directions,  on  one  as  if  the  section 
were  parallel  to  an  octahedron  and  on  the  other  as  if  it 
were  parallel  to  a  hexoctahedron.  The  third  portion  ex- 
hibits at  first  sight  no  octahedral  figures,  but  appears  like 
an  ataxite.  On  close  examination,  however,  indications  of 
octhedral  figures  can  be  discerned  in  this  portion  also.  The 


FIG.  41. —  Tesselated  octahedral  figures  seen  in  one  of  the   Bethany  meteorites. 
Some  of  the  lamellae  follow  the  lines  of  a  cube,  others  those  of  an  octahedron. 

best  explanation  of  the  peculiar  structure  seems  to  be  that 
of  Berwerth,*  who  regards  the  mass  as  made  up  of  three 
individuals  twinned  according  to  the  spinel  law,  but  one  of 
the  individuals  suffered  some  subsequent  molecular  altera- 
tion. 

Some  iron  meteorites  on  etching  do  not  exhibit  the  broad, 
lamellar  figures  which  have  been  described  for  octahedral 
meteorites.  Their  surface  appears,  except  for  occasional 
inclusions,  practically  uniform  and  homogeneous.  Yet  on 
close  examination  their  surfaces  will  be  found  to  be  crossed 
here  and  there  and  in  different  directions  by  long,  straight, 
narrow,  slightly  depressed  lines.  Scattered  among  these 
are  shorter  lines,  also  running  in  various  directions.  Such 
lines  were  first  observed  and  described  in  detail  by  Neumann 

*Sitzb.  Akad.  d.  Wiss.,  Wien.,  1902,  HI. 


STRUCTURE   OF   METEORITES 


97 


and  they  are  therefore  generally  known  as  Neumann  lines. 
Meteorites  which  exhibit  them  are  also  found  to  possess  a 
cubic  cleavage  which  can  best  be  observed  by  cutting  a 
section  of  the  meteorite  partly  in  two  and  then  breaking 
the  remainder.  The  fractured  surface  then  presents  an  ap- 
pearance like 
that  of  broken 
galena.  The 
Neumann  lines 
always  exhibit 
some  definite 
relation  to  the 
cubic  struc- 
ture, by  either 
running  as 
diagon  als  of 
faces  or  to 
central  points 
of  a  cubic  edge. 
The  appear- 
ance of  these 
lines  and  their 
relation  to  a 
cube  are  shown 
in  the  accom- 
panying figure 
(Fig.  42)  as 
drawn  by 
Huntington* 
from  a  section 

of  Coahuila.  The  lines  are  regarded  as  representing  narrow 
lamellae  more  easily  dissolved  by  acid  than  the  intervening 
portions.  They  lie  in  twinning  relation  to  the  main  indi- 
vidual. According  to  Linck|  the  twinning  plane  may  be 
the  octahedron  or  both  the  twinning  plane  and  the  growth 
plane  may  be  the  trisoctahedron,  211.  Irons  which  show 
the  Neumann  lines  also  exhibit  an  oriented  sheen.  This  is 


FIG.  42.  Upper  figure  shows  Neumann  lines  seen  on  a 
section  of  the  Coahuila  iron.  Lower  figure  shows  the 
relations  of  these  lines  to  those  of  a  cube.  After  Hunt- 
ington. 


*Am.  Jour.  Sci.,  3,  32,  284. 

fZeitschr.  fur  Kryst.,  1892,  20,  209-215. 


98  METEORITES 

believed  to  be  caused  by  reflection  of  light  (i)  from  minute, 
square  pits  which  are  negative  crystals  of  a  tetrahexahedron 
and  (2)  from  the  Neumann  lines.  Owing  to  the  various 
cubic  features  which  characterize  irons  of  this  type,  they  are 
known  as  hexahedrites.  They  form  a  small  but  well- 
marked  group.  The  only  member  of  the  group  observed  to 
fall  is  Braunau.  Other  typical  hexahedrites  are  Coahuila, 
Hex  River,  Lick  Creek,  Murphy,  Nenntmannsdorf,  and 
Scottsville.  These  exhibit  an  uninterrupted  cubic  structure 
and  are  known  as  normal  hexahedrites.  Others  which  are 
cubic  show  a  more  or  less  coarse-granular  structure  and  are 
known  as  granular  hexahedrites.  The  individual  grains  on 
these  show  Neumann  lines  which  differ  in  direction.  The 
size  and  shape  of  these  grains  also  varies  in  different  meteor- 
ites. Bingera,  Holland's  Store,  Indian  Valley,  Summit,  and 
Tombigbee  River  are  examples  of  this  group.  While  the 
normal  hexahedrites  appear  alike,  they  exhibit  considerable 
difference  in  their  resistance  to  acid.  Some,  like  Fort 
Duncan,  dissolve  with  difficulty  while  Lick  Creek  and 
Scottsville  etch  very  easily. 

Other  iron  meteorites  on  etching  show  neither  octahedral 
figures  nor  Neumann  lines,  and  neither  octahedral  nor  cubic 
cleavage.  Some  show  a  fine-granular  structure  but  others 
even  under  the  microscope  exhibit  no  division  into  grains 
which  can  be  detected.  They  are,  therefore,  except  for 
accessory  minerals,  quite  structureless.  Peculiar  streaks  or 
clouds  characterize  some,  but  they  are  neither  octahedral  or 
cubic  in  their  arrangement.  To  this  third  group  of  iron 
meteorites  the  name  of  ataxites  is  applied,  the  name  mean- 
ing "without  arrangement."  Such  meteorites,  because  of 
their  lack  of  characteristic  figures,  form  a  difficult  group  to 
distinguish  from  terrestrial  irons.  Some  of  them  are 
regarded  by  Berwerth  as  showing  traces  of  octahedral 
structure  and  to  have  been  produced  by  heating  of  octa- 
hedral meteorites.*  Such  an  origin  for  some  ataxites  is 
rendered  probable  by  the  fact  that  heating  an  octahedral 
iron  destroys  the  octahedral  structure,  as  shown  in  the 
accompanying  figure  (Fig.  43).  The  upper  figure  shows  a 

*Sitzb.  Wien  Akad.,  1905,  Vol.  114. 


STRUCTURE   OF   METEORITES 


99 


section  of  Toluca  exhibiting  the  usual  etching  figures  of 
that  meteorite,  while  the  lower  figure  shows  the  change 
made  in  the  appearance  of  the  iron  by  heating  it  to  a  tem- 
perature of  950°  C.  for  seven  hours.  The  octahedral  struc- 
ture is  practically  destroyed  and  an  appearance  closely 
resembling  that  of  many  of  the  ataxites  is  produced.  On 
the  other  hand  not  all  ataxites  can  have  been  produced  in 
this  way  since  some  of  them  have  too  high  a  content  of 
nickel  to  have  had 
octahedral  struc- 
ture. The  ataxites 
fall  for  the  most 
part  as  regards 
composition  into 
two  groups,  one 
being  high  (15  to 
20  per  cent)  in 
nickel,  the  other 
low  (5  to  7  per 
cent).  A  few  are 
intermediate  be- 
tween these  in  their 
nickel  content. 

A  study  by  the 
writer*  of  the  com- 
position of  the  iron 
meteorites  showed 
that  a  definite  re- 
lation apparently 
exists  between 
their  composition 
and  structure  or 
that  their  com- 
position apparently  controls  their  structure.  Thus  the 
hexahedrites  all  contain  about  6  per  cent  of  nickel,  the  oc- 
tahedrites  from  7  to  15  per  cent  and  one  group  of  the  atax- 
ites a  still  higher  percentage.  It  appears,  therefore,  that 
in  cooling  from  the  original  magma,  a  meteoric  iron  which 

*Pubs.  Field  Mus.  Geol.  Ser.,  1907,  3,  106. 


FIG.  43. —  Effect  of  heating  a  section  of  the  Toluca 
meteorite  for  7  hours  at  950°  C.  Upper  figure, 
before  heating.  Lower  figure,  after  heating. 
The  heating  destroyed  the  lamellar  structure  and 
produced  an  appearance  like  that  of  some  ataxites. 
After  Berwerth. 


100  METEORITES 

contains  5  to  7  per  cent  of  nickel  will  crystallize  in  the  cubic 
form,  one  containing  between  7  and  15  per  cent  will  crys- 
tallize in  the  octahedral  form,  and  one  containing  a  percent- 
age of  nickel  greater  than  this  will  not  crystallize  at  all. 
Further,  among  the  octahedral  irons  the  percentage  of 
nickel  will  influence  the  width  of  the  bands,  the  bands  being 
narrower  as  the  percentage  of  nickel  increases. 

Accessory  minerals  occur  in  all  the  iron  meteorites.  Their 
position  and  form  may  or  may  not  be  independent  of  the 
structure  of  the  nickel-iron.  Thus  in  the  octahedral  irons 
pyrrhotite  may  occur  in  nodules  of  various  shapes  and  sizes 
without  regular  arrangement,  or  it  may  occur  in  plate-like 
forms  arranged  parallel  to  the  faces  of  a  cube  or  dodeca- 
hedron. In  the  latter  case  the  term  Reichenbach  lamellae 
is  applied  to  the  forms.  Schreibersite  may  likewise  be  ir- 
regularly distributed  or  it  may  occur  in  plate-like  forms 
arranged  according  to  the  planes  of  a  dodecahedron.  The 
latter  forms  are  known  as  Brezina  lamellae.  Graphite  no- 
dules also  occur  in  the  octahedral  irons  but  they  are  always 
irregularly  distributed.  They  may  be  individual  or  inter- 
grown  with  pyrrhotite  or  schreibersite.  Frequently,  inclu- 
sions of  these  minerals  are  surrounded  by  a  border  of  kama- 
cite.  Within,  this  follows  the  outline  of  the  inclusion  but 
on  its  outer  side  it  is  not  in  accord  with  the  octahedral  struc- 
ture. Cohenite  is  a  common  ingredient  of  the  coarse  octa- 
hedrites,  usually  in  the  form  of  prismatic  crystals  lying  in 
the  bands  of  kamacite.  Among  the  hexahedrites,  schrei- 
bersite in  the  needle-like  form  known  as  rhabditeis  a  common 
constituent.  It  is  usually  regularly  distributed  in  oriented 
positions.  Schreibersite  also  frequently  occurs  in  the  hex- 
ahedrites in  the  form  of  large  inclusions  resembling  hiero- 
glyphic characters.  Pyrrhotite  is  not  as  abundant  in  the 
hexahedrites  as  in  the  octahedrites  but  may  occur  in  both 
oriented  and  non-oriented  positions.  Daubreelite  is  com- 
mon and  characteristic  of  the  hexahedrites,  usually  occur- 
ring intergrown  with  pyrrhotite  in  parallel  plates.  Graphite 
is  of  rare  occurrence  in  the  hexahedrites. 

Among  the  ataxites  accessory  constituents  are  usually 
rare  and  of  small  size.  When  they  do  occur  a  zone  of 


STRUCTURE   OF   METEORITES  ^j  ;  \/     101 


slightly  different  appearance  from  the  rest  of  {He  ^ 
usually  surrounds  them  in  much  the  same  manrieFas  a  bor- 
der of  kamacite  surrounds  accessory  minerals  in  the  octahe- 
dral irons.  Two  or  three  of  the  ataxites  are  rich  in  rhabdite. 
Other  minerals  besides  those  mentioned  which  sometimes 
take  part  in  the  structure  of  iron  meteorites  are  chromite, 
diamond,  amorphous  carbon,  lawrencite,  chrysolite,  forste- 
rite,  and  quartz.  No  marked  feature  so  far  as  known  at- 
tends the  distribution  of  these.  Brezina*  gives  the  following 
as  the  order  of  cooling  or  solidification  of  the  constituents 
of  the  iron  meteorites:  Daubreelite,  pyrrhotite,  graphite, 
schreibersite,  cohenite,  chromite,  swathing  kamacite,  band 
kamacite,  taenite,  and  plessite. 

STRUCTURE  OF  IRON-STONE  METEORITES 

The  iron-stone  meteorites  pass,  as  has  been  said,  into  the 
iron  meteorites  on  the  one  hand  and  the  stone  meteorites  on 
the  other.  Yet  within  their  boundaries  they  present  well- 
marked  characteristics  of  structure.  The  pallasites,  which 
most  nearly  resemble  the  iron  meteorites,  consist  of  a  sponge- 
like  mass  of  nickel-iron,  the  pores  of  which  are  filled  with 
chrysolite.  The  proportion  of  metal  to  silicate  in  pallasites 
varies  in  different  falls  and  in  individuals  of  the  same  fall. 
Thus  in  individuals  of  Brenham  part  has  the  pallasite  struc- 
ture and  part  the  octahedrite  structure,  and  while  the  ma- 
jority of  the  individuals  of  the  fall  are  pallasites,  some  are 
entirely  octahedrites.  In  all  pallasites  the  metal  shows 
octahedral  figures  on  etching.  The  chrysolite  element  is 
usually  in  the  form  of  rounded  or  angular  grains.  Some  of 
the  grains  attain  a  diameter  of  a  centimeter  or  more,  but  a 
size  of  about  half  a  centimeter  is  more  common.  Often  the 
grains  exhibit  crystal  planes,  but  a  rounding  of  the  solid 
angles,  as  if  the  surface  had  been  fused,  usually  obscures 
the  crystal  forms.  The  grains  are  usually  surrounded  by  a 
band  of  kamacite  which  accommodates  itself  to  their  form. 
This  shows  that  the  metal  solidified  subsequent  to  the  si- 
licate. In  the  other  groups  of  iron-stone  meteorites  the 
sponge-like  structure  is  far  less  noticeable  or  if  it  occurs, 

*Denkschr.  Wien  Akad.,  1905,  88,  641. 


102  METEORITES 

tnefe  is- greater  irregularity  in  the  size  and  shape  of  the 
pores  in  which  the  silicates  occur.  The  metal  tends  to  ag- 
gregate in  large  nodules  at  times  and  the  silicates  do  like- 
wise. Again  there  may  be  a  uniform  dotting  of  metal  as 
seen  on  a.  section  surface,  with  similar  dotting  of  silicates 
interspersed.  By  the  gradual  diminution  of  the  amount  of 
metal,  these  iron-stone  meteorites  of  which  Mincy  and  Crab 
Orchard  are  good  illustrations,  pass  over  to  the  structure  of 
the  stone  meteorites. 

STRUCTURE  OF  STONE  METEORITES 

CHONDRITIC   STRUCTURE 

A  structure  peculiar  to  about  90  per  cent  of  all  stone 
meteorites  consists  in  their  being  made  up  of  rounded  grains 
orspherules.  These  grains  or  spherules  are  named  chondri, 
(dim.  chondrules)  from  the  Greek  %6v&po$,  a  grain,  and 
meteorites  largely  or  partly  made  up  of  them  are  known  as 
chondrites.  In  size  chondri  vary  from  that  of  a  walnut  to 
a  dust-like  minuteness.  The  larger  number  are  about  the 
size  of  millet  seeds.  The  form  of  chondri  is  generally  spher- 
oidal, but  varies  from  essentially  spherical  to  mere  irregular 
fragments.  Some  chondri  are  flattened  or  oval  and  others 
show  apparent  deformation  subsequent  to  their  origin.  In 
the  latter,  depressions  or  projections  occur  which  often  look 
as  if  a  hard  chondrus  had  pressed  against  another  soft  one 
during  the  process  of  formation.  The  deformed  chondri 
pass  by  every  gradation  into  those  which  appear  to  be  rock 
fragments  with  rounded  angles.  The  surface  of  the  chon- 
drus is  rarely  smooth,  being  usually  rough  or  knobbed. 
From  many  friable  meteorites  individual  chondri  can  easily 
be  isolated,  but  if  the  meteorite  is  at  all  coherent  the  chon- 
dri break  with  the  rest  of  the  mass.  The  color  of  chondri 
is  usually  white  or  gray,  but  some  are  brown  to  black.  As 
they  are  often  of  the  same  substance  as  the  groundmass  in 
which  they  are  imbedded  they  may  differ  little  in  color  from 
it.  On  this  account  and  on  account  of  an  ill-defined  contour 
they  may  be  overlooked  and  a  crystal  may  be  considered 
porphyritic,  which  is  really  part  of  a  chondrus.  Usually, 


STRUCTURE   OF   METEORITES  103 

however,  the  chondri  are  plainly  marked  on  a  polished  sec- 
tion by  differences  in  color  and  contour.  In  structure  chon- 
dri may  themselves  be  granular,  porphyritic  or  coarsely  or 
finely  fibrous.  They  may  consist  of  a  single  crystal  indi- 
vidual, in  which  case  they  are  said  to  be  monosomatic,  or 
of  several  individuals,  when  they  are  said  to  be  polysomatic. 
True  monosomatic  chondri  are  confined  almost  exclusively 
to  the  mineral  chrysolite.  They  may  be  known  by  their 
simultaneous  extinction  in  polarized  light.  Polysomatic 
chondri  may  be  made  up  of  different  minerals  as  well  as 
different  individuals  and  may  show  more  than  one  kind  of 
structure,  i.  e.,  a  chondrus  may  be  granular  in  one  portion 
and  fibrous  in  another.  The  following  minerals  are  noted 
by  Tschermak  as  forming  chondri,  their  relative  abundance 
being  in  the  order  named:  Chrysolite,  bronzite,  augite,  pla- 
gioclase,  glass,  and  nickel-iron.  Chrysolite  chondri  usually 
contain  large  quantities  of  glass  of  a  dark  brown  color. 
This  may  be  arranged  (a)  in  the  form  of  alternate  layers, 
in  which  case  a  marked  rod-like  or  lamelliform  appearance 
is  produced,  (b)  forming  a  base  in  which  the  mineral  is  de- 
veloped porphyritically,  (c)  occurring  in  the  center  of  a 
crystal,  or  (d)  forming  a  net-work.  Polysomatic  chondri 
of  the  latter  sort  are  especially  liable  to  be  mistaken  for 
those  of  enstatite  since  they  simulate  the  fibrous  appear- 
ance of  the  latter.  Occasionally  the  crystallization  may 
have  proceeded  only  far  enough  to  produce  skeletal  or 
branching  growths  of  the  mineral  among  glass.  Both  mon- 
osomatic and  polysomatic  chrysolite  chondri  may  have  the 
arrangement  of  a  well-marked  rim  about  a  spherical  interior. 
This  rim  may,  in  the  polysomatic  chondri,  be  composed  of 
many  individuals.  Such  a  rim  is  often  dark  from  a  content 
of  iron  and  pyrrhotite.  Chromite,  either  in  minute  grains 
or  in  dust-like  aggregations,  also  forms  a  common  inclusion 
usually  near  the  surface  of  the  chondrus.  The  quantity  of 
opaque  inclusions  may  be  so  great  as  to  give  the  chondrus 
a  black  color.  Such  chondri  associated  with  those  of  light 
color  are  to  be  found  in  the  stones  of  Knyahinya,  Mezo- 
Madaras,  and  others.  The  constituent  minerals  of  such 
chondri  are  chiefly  chrysolite  and  enstatite.  Enstatite 


104 


METEORITES 


chondri  are  usually  of  a  finely  fibrous  character.  The 
fibers  instead  of  radiating  from  a  center  as  do  those  of 
spherulites  usually  diverge  from  an  eccentric  point  (Fig.  44). 
This  eccentric  arrangement  constitutes  one  of  the  most 
marked  features  of  these  chondri  and  separates  them 
sharply  from  any  formation  seen  in  terrestrial  rocks.  The 


FIG.  44. —  Microscopic  section  of  the  Homestead  meteorite,  showing  an 
eccentric  radiating  enstatite  chondrus  and  a  porphyritic  and  a  granular 
chrysolite  chondrus.  X65.  After  Tschermak. 

enstatite  chondri  have  less  glass  than  those  of  chrysolite. 
Monosomatic  chondri  of  enstatite  have  never  been  observed, 
the  large  crystal  individuals  showing,  as  a  rule,  no  tendency 
to  a  spherical  form.  Besides  enstatite  chondri  having  an 
eccentric  arrangement  of  fibers,  there  occur  those  which  are 
confusedly  fibrous,  and  these  may  pass  into  those  which 


STRUCTURE   OF   METEORITES  105 

have  a  netted  appearance  from  crossing  fibers.  Such  chon- 
dri,  cut  at  right  angles  to  the  fibers,  show  the  fibers  to  have 
a  concentric  arrangement.  The  chondri  already  mentioned, 
which  are  granular  in  part  and  in  part  fibrous,  are  usually 
made  up  of  the  two  minerals  chrysolite  and  enstatite.  These 
minerals  may  be  present  in  about  equal  quantity  or  either 
may  be  in  excess.  Usually  the  enstatite  together  with  glass 
appears  to  occupy  the  intervening  spaces  between  the 
chrysolite  grains,  indicating  that  it  is  of  later  formation. 
Augite  chondri  are  not  common  but  occasionally  occur. 
They  often  show  a  structure  which  indicates  repeated 
twinning.  The  mineral  may  appear  also  in  the  form  of 
grains,  usually  of  a  green  color.  These  grains  can  be  dis- 
tinguished from  chrysolite  by  their  behavior  in  polarized 
light.  Chondri  containing  plagioclase  in  any  large  quantity 
are  rare  but  have  been  observed  by  Tschermak  in  the  stone 
of  Dhurmsala.  The  plagioclase  alternates  in  bands  with 
chrysolite  and  is  in  excess.  .Chondri  also  occur  which  are 
composed  almost  exclusively  of  glass,  the  only  indication  of 
the  presence  of  other  minerals  being  in  the  presence  of  forked 
microlites  which  may  be  referred  to  enstatite.  Occasionally 
these  microlites  are  of  a  pronounced  star-like  form.  Chondri, 
or  at  least  rounded  spheres  of  nickel-iron,  occur  in  some 
meteorites,  but  are  not  common.  All  gradations  occur  from 
chondri  which  contain  grains  of  nickel-iron  to  complete 
spheres  of  nickel-iron.  In  the  stone  of  Renazzo  such 
spheres  have  a  covering  of  brown  glass.  Some  of  the 
spheres  or  rounded  fragments  also  contain  pyrrhotite,  but 
pyrrhotite  of  itself  has  never  been  seen  to  form  chondri.  A 
more  or  less  complete  rim  of  metal  is  characteristic  of  many 
chondri.  The  metal  may  occur  in  the  form  of  rounded 
grains  or  as  a  continuous  periphery.  It  has  been  suggested 
by  Daubree  that  such  a  rim  shows  that  the  chondrus  has 
been  subject  to  the  reducing  action  of  hydrogen.  Besides 
the  chondri  colored  black  by  inclusions  of  iron  and  pyrrhotite, 
previously  described,  black  chondri  which  consist  chiefly 
of  maskelynite  or  granular  plagioclase,  occur  in  the  stones  of 
Alfianello,  Chateau  Renard,  and  others.  These  chondri  are 
transparent  and  colorless  about  their  rim,  but  in  the  interior 


106 


METEORITES 


are  totally  black  from  inclusions  of  angular  or  rounded 
grains,  some  of  which  are  shown  by  their  brown  color  to  be 
pyrrhotite.  A  gathering  of  grains  at  the  center  distinguishes 
these  chondri  from  those  previously  described  in  which  the 
rim  was  black.  Besides  complete  chondri,  fragments  repre- 
senting various  portions  of  a  complete  chondrus  occur. 


FIG.  45. —  Microscopic  section  of  the  Dhurmsala  meteorite,  showing  a 
large,  somewhat  porphyritic  chrysolite  chondrus  enclosing  a  smaller  one. 
X8.  After  Tschermak. 

These  may,  on  account  of  their  shape,  be  very  misleading, 
as  they  may  be  taken  for  porphyritic  individuals  or  for 
portions  of  a  foreign  stone  if  their  previous  chondritic  origin 
is  not  recognized.  Tschermak  states  that  fragments  of 
chondri  are  most  numerous  in  the  stones  whose  chondri 
have  well-marked  contours.  So  far  as  the  association  of 


STRUCTURE   OF   METEORITES 


107 


chondri  is  concerned  it  is  to  be  noted  that  chondri  of  more 
than  one  of  the  kinds  above  described  usually  occur  promis- 
cuously scattered  through  the  same  stone.  There  is  no 
gathering  of  them  into  groups  according  to  the  minerals 
they  contain.  Occasionally  one  chondrus  encloses  another 
(Fig.  45),  and  still  more  rarely  two  may  be  joined  together. 


FIG^  46. —  Microscopic  section  of  the  Mezo  Madaras  meteorite,  showing 
fragments  of  chondri.  Fragments  of  enstatite,  chrysolite,  and  nickel- 
iron  chondri  can  be  recognized.  X?o.  After  Tschermak. 

Broken  fragments  of  chondri  commonly  occur  in  the  stone 
with  complete  chondri.  Two  fragments  of  the  same  chon- 
drus are,  however,  rarely  if  ever  found  in  juxtaposition. 
Hence  there  must  have  been  considerable  separation  of 
the  fragments  before  consolidation  of  the  stone  took  place, 
(Fig.  46). 


108  METEORITES 

The  conditions  which  have  brought  about  the  formation 
of  chondri  are  not  well  understood,  though  the  question  has 
been  much  discussed  and  various  hypotheses  have  been  sug- 
gested. The  views  of  earlier  observers  were  to  the  effect 
that  the  chondri  represented  fragments  of  pre-existing  rock 
which,  by  oscillation  and  consequent  attrition  had  obtained 
a  spherical  form.  Sorby  regarded  chondri  as  produced  by 
cooling  and  aggregation  of  minute  drops  of  melted  stony 
matter.  Tschermak  considers  their  origin  similar  to  that 
of  the  spherules  met  with  in  volcanic  tuffs  which  owe  their 
form  to  prolonged  explosive  activity  in  a  volcanic  throat, 
breaking  up  the  older  rocks  and  rounding  the  particles  by 
constant  attrition. 

Different  views  are,  however,  held  by  Brezina,  Wads- 
worth,  and  others,  these  believing  that  the  chondri  have 
been  produced  by  rapid  and  arrested  crystallization  in  a 
molten  mass. 

Objections  to  theories  of  the  first  class  are  to  be  found  (i) 
in  the  fact  that  the  chondri  usually  have  rough-knobbed 
surfaces  instead  of  smooth  ones,  such  as  attrition  might  be 
expected  to  produce;  (2)  in  the  regularly  eccentric  form  of 
most  enstatite  chondri,  which  attrition  would  be  likely  to 
destroy;  and  (3)  in  the  fact  that  fragments  of  a  pre-existing 
rock  ought  to  show  the  constitution  of  the  rock  as  a  whole 
instead  of  a  specialized  structure.  Objections  to  theories  of 
the  second  class  are  to  be  found  chiefly  in  the  clearly  frag- 
mental  nature  of  most  chondritic  meteorites.  It  is  in  their 
variation  from  the  surrounding  ground  mass  and  in  the 
eccentric  arrangement  of  their  fibers  that  chondri  differ 
chiefly  from  the  spherulites  of  terrestrial  rocks. 

Stone  meteorites  without  chondri,  the  achondrites,  usually 
differ  considerably  in  structure  from  the  chondrites  although 
various  gradations  are  to  be  seen.  Porphyritic,  ophitic 
and  granular  structures  occur  and  the  resemblance  to  ter- 
restrial rocks  is  much  closer  than  in  the  chondrites.  There 
are  differences,  however,  in  the  fact  that  the  granular 
meteorites  are  only  of  fine  grain  and  the  ophitic  and  por- 
phyritic  ones  vary  in  size  of  grain. 

Chassigny   shows   the   most   typical   uniformly   granular 


STRUCTURE   OF   METEORITES  109 

structure,  consisting  as  it  does  of  isometric  grains  resting  near 
one  another.  Occasionally  angular  gaps  are  filled  by  weak, 
doubly  refracting,  transparent,  maskelynite-like  substances. 
Ibbenbiihren  and  Manegaum,  both  consisting  of  enstatite, 
are  similar,  although  in  Ibbenbiihren  the  grain,  according  to 
Tschermak,  is  not  quite  uniform  since  small  grains  lie  be- 
tween the  larger  ones.  Angra  dos  Reis  is  distinguished  by  a 
fine-granular  structure  and  is  so  loose  that  pieces  can  be 
rubbed  between  the  fingers.  Lodran  also  shows,  with  the 
exception  of  the  fine  iron  network,  a  structure  of  isometric 
grains  which  are  numerously  bounded  by  crystal  faces  com- 
posed of  nickel-iron.  Nowo  Urei  possesses  a  peculiar  struc- 
ture. Between  grains  of  olivine  and  augite  there  lies  a  fine- 
grained aggregate  consisting  of  nickel-iron,  a  graphitic 
substance,  and  diamond.  It  seems  to  be  in  the  form  of  a 
dark  network  with  its  meshes  filled  by  silicates  since  a  great 
number  of  dark  particles  are  bordered  by  silicate  grains. 
Some  varieties  of  magnetite-olivinite  from  Taberg  in 
Sweden  show  similar  structure,  the  magnetite  appearing  in 
the  same  form  as  the  nickel-iron  and  carbonaceous  sub- 
stances in  Nowo  Urei. 

All  eukrites  and  shergottites  show  an  ophitic  structure. 
This  is  wont  to  be  better  developed  the  coarser  the  grain 
and  can  usually  be  recognized  macroscopically  in  represen- 
tatives of  these  groups.  Anorthite  appears  in  lath-shaped 
individuals  and  augite  fills  the  spaces.  In  Jonzac  the  ophitic 
structure  is  beautifully  and  uniformly  developed  and  the 
grain  coarse.  The  plagioclases  are  5  mm.  in  length  and 
sometimes  12  mm.  In  Stannern  and  Juvinas  the  grain  is 
variable  in  size  not  only  in  different  stones  but  in  one  and 
the  same.  This  change  is  so  strong  in  Stannern  that  Tscher- 
mak considered  the  meteorites  as  consisting  of  three  kinds 
of  stones,  and  distinguished  coarse-granular,  radiated,  and 
compact  portions.  Shergotty  shows  on  the  other  hand  very 
uniform  size  of  grains.  According  to  Tschermak  there  oc- 
cur in  the  howardites  portions  with  ophitic  structure  which 
he  regarded  as  fragments  of  eukrites.  In  an  essentially  uni- 
form granular  structure  it  is  common  to  find  single  individ- 
uals more  or  less  sharply  distinguished  by  their  size,  also 


110  METEORITES 

partly  well-formed  crystals  and  partly  fragmental  individ- 
uals. As  a  rule  they  are  the  same  minerals  as  those  form- 
ing the  chief  mass  of  the  stone,  but  exceptionally  consist 
of  other  constituents.  Thus  in  Bustee  appear  diopside  and 
enstatite;  in  Shalka  bronzite;  in  Manegaum  chrysolite;  in 
Bishopville  enstatite  and  accessory  plagioclase;  in  the  how- 
ardites  anorthite,  pyroxene,  and  chrysolite.  The  ortho- 
rhombic  pyroxenes  at  times  reach  the  size  of  a  centimeter. 
Bustee  shows  an  almost  porphyritic  structure,  since  the 
large  crystals  are  very  prominent  in  a  fine-grained  ground 
mass.  In  Shalka  the  larger  individuals  are  grouped  here 
and  there  so  that  the  coarser  crystalline  portions  can  be 
seen. 

The  mesosiderites  also  consist  essentially  of  a  uniformly 
granular  aggregate  of  iron,  olivine,  enstatite,  and  to  some 
extent  plagioclase  in  which  the  olivine  often  appears  por- 
phyritic and  at  times  in  crystals  which,  according  to  Reich- 
enbach,  in  Hainholz  reach  a  size  of  \]A.  centimeters,  and 
according  to  Kunz  in  Mincy  10  centimeters.  In  the  gra- 
hamites,  which  are  nearly  related  to  the  mesosiderites  and 
are  distinguished  only  by  the  greater  quantity  of  plagio- 
clase, the  structure  is  variable.  According  as  the  plagio- 
clase or  the  augite  reaches  the  stronger  development,  the 
structure  appears  either  ophitic  or  granular  and  porphyritic, 
the  olivines  reaching,  according  to  Brezina,  a  size  of  iy£ 
centimeters,  but  since  in  the  mesosiderites  and  grahamites 
the  nickel-iron  appears  often  in  the  form  of  chondri,  and 
according  toTschermak  glass  is  sometimes  present,  no  typ- 
ical crystalline  granular  structure  can  be  said  to  be  present. 
Also  in  ophitic  structure  crystals  of  augite  or  anorthite 
appear  often  porphyritic.  In  many  achondrites,  mesosid- 
erites and  grahamites  portions  occur  which  have  the  ap- 
pearance of  concretionary  formations  and  have  a  more  or 
less  sharp  boundary.  As  a  rule  only  the  quantity  of  the 
constituent  seems  to  be  different  from  that  of  the  main 
mass,  but  at  times  a  different  structure  may  be  seen.  Thus 
in  Juvinas  portions  occur  without  ophitic  structure  3  cen- 
timeters in  size,  dark  and  rich  in  augite  and  metallic  particles. 
Perhaps  here  also  belong  the  already  mentioned  granular, 


STRUCTURE   OF   METEORITES  111 

hard,  fine-grained  and  easily  separable  portions  of  Man- 
bhoom  which  are  2  centimeters  in  size  and  resemble  the 
howardites.  Reichenbach  observed  in  Hainholz  a  com- 
pactness of  structure  toward  the  peripheral  portion  of  the 
meteorite.  As  a  rule  crystalline  granular  meteorites  possess 
a  compact  structure  but  the  howardites  are  an  exception 
and  form  the  passage  from  the  achondrites  to  the  chondrites. 

Large  cavities  in  which  the  constituents  show  crystals 
are  especially  well  developed  in  Juvinas.  Such  druses  fur- 
nished Rose  measurable  crystals.  Estherville  also  shows 
occasionally  a  drusy  structure.  Both  Reichenbach  and 
Newton  observed  that  the  single  constituents  of  the  stone 
meteorites,  silicates  or  nickel-iron,  often  show  a  regular  ar- 
rangement when  light  is  reflected  from  a  fractured  surface 
or  from  polished  faces.  To  see  this  arrangement  requires, 
of  course,  careful  examination,  but  with  some  care  parallel 
systems  of  lines  crossing  at  right  angles  may  be  observed. 
The  lines  seldom  run  straight,  usually  crooked.  They  are 
abundantly  interrupted  and  often  return  on  themselves. 
Recognition  of  the  lines  is  the  most  difficult  in  the  mete- 
orites rich  in  chondri  and  of  coarse  structure;  also  if  the 
structure  is  fine  and  uniform.  Bluff,  Crab  Orchard,  Hes- 
sle,  Pultusk,  Renazzo,  Siena,  Tomhannock  Creek,  Weston, 
Vaca  Muerta,  and  Wold  Cottage,  furnish  good  examples  of 
these  lines.  Newton  thought  that  these  line  systems  indi- 
cated that  the  same  forces  that  produced  octahedral  figures 
in  the  iron  meteorites  had  controlled  the  arrangement  of  the 
iron  particles  in  the  stone  meteorites,  and  compared  the 
structure  with  that  of  graphic  granite. 

As  a  rule  the  different  stones  of  one  and  the  same  fall  show 
in  all  essential  points  the  same  structure.  Exceptions  how- 
ever occur.  Of  the  numerous  stones  which  fell  at  Home- 
stead and  which  show  the  habit  of  a  normal  gray  chondrite, 
one  differed.  This  was  a  compact,  dark  or  grayish  green, 
poor-in-chondri  stone.  Among  1200  stones  of  Pultusk  in- 
vestigated by  Rath  one  was  free  from  chondri  and  poor  in 
metallic  constituents.  Rath  compared  its  habit  with  that 
of  Chassigny  and  stated  that  it  possessed  hardly  any  simi- 
larity with  a  chondrite.  Brezina  distinguished  it  on  the 


112  METEORITES 

ground  of  its  mineralogical  composition  as  amphoterite-like. 
According  to  Denza,  of  the  stones  which  were  simultaneous 
in  fall  at  Motta  dei  Conti  and  Villeneuve  those  falling  at 
the  former  locality  were  richer  in  metallic  constituents,  more 
transparent  and  of  finer  grain.  According  to  Tschermak,  of 
the  stones  which  fell  at  Stannern,  some  of  the  smaller  were 
compact  and  homogeneous,  or  were  plainly  crystalline  and 
of  breccia-like  character. 


CHAPTER  XI 

COMPOSITION   OF  METEORITES 

ELEMENTS 

The  following  elements  have  been  found  in  meteorites  in 
amounts  sufficient  for  quantitative  determination: 

Aluminum  Iridium  Potassium 

Argon  Iron  Radium 

Calcium  Magnesium  Ruthenium 

Carbon  Manganese  Silicon 

Chlorine  Nickel  •  Sodium 

Chromium  Nitrogen  Sulphur 

Cobalt  Oxygen  Tin 

Copper  Palladium  Titanium 

Helium  Phosphorus  Vanadium 

Hydrogen  Platinum 

These  occur  as  follows: 

Aluminum  occurs  combined  with  silica  in  the  stony 
meteorites,  chiefly  in  feldspars,  and  perhaps  also  as  a  con- 
stituent of  some  pyroxenes  and  chromites.  It  is  much  less 
abundant  than  in  terrestrial  crustal  rocks. 

Argon  has  been  found  as  an  included  gas. 

Calcium  occurs  in  stony  meteorites  as  an  ingredient  of 
anorthite  and  pyroxene,  also  in  the  sulphide  oldhamite. 

Carbon  occurs  (i)  amorphous,  (2)  as  graphite,  (3)  as  dia- 
mond, (4)  forming  carbides  of  iron,  nickel  and  cobalt  and 
silicon,  (5)  as  a  constituent  of  carbon  monoxide,  dioxide, 
and  marsh  gas,  (6)  as  a  constituent  of  other  hydrocarbons, 
and  (7)  probably  as  carbonates. 

Chlorine  is  knpwn  to  occur  only  in  combination  with  iron 
to  form  lawrencite,  but  other  modes  of  its  occurrence  are 
not  unlikely. 

Chromium  occurs  in  combination  with  iron  and  sulphur 
to  form  daubreelite,  with  iron  and  oxygen  to  form  chromite, 

113 


114       _  METEORITES 

and  probably  also  in  the  metallic  state  alloyed  with  iron  and 
nickel. 

Cobalt  occurs  alloyed  with  iron  and  nickel  in  nickel-iron 
and  takes  part  with  these  metals  in  the  composition  of 
carbides,  phosphides,  oxides,  and  probably  sulphides. 

Copper  occurs  in  the  form  of  an  alloy  in  nickel-iron,  from 
which  it  is  apparently  never  absent. 

Helium  has  been  found  as  an  included  gas. 

Hydrogen  occurs  as  a  gas  either  pure  or  combined  with 
carbon.  It  also  takes  part  in  the  composition  of  hydro- 
carbons and  perhaps  ammoniacal  salts.  If  the  water 
sometimes  found  in  meteorites  is  of  pre-terrestrial  origin, 
this  also  represents  a  hydrogen  compound. 

Iridium  occurs  alloyed  with  nickel-iron.  It  is  found  only 
in  traces. 

Iron,  the  most  important  constituent  of  meteorites,  is 
chiefly  alloyed  with  nickel,  cobalt,  and  copper.  It  also  com- 
bines with  sulphur,  phosphorus,  carbon,  chlorine  and  oxygen 
to  form  sulphides,  phosphides,  carbides,  chlorides,  and 
oxides.  In  combination  with  sulphur  and  chromium  it 
forms  daubreelite  and  with  chromium  and  oxygen,  chromite. 
It  is  also  an  important  ingredient  of  chrysolite  and  the 
pyroxenes. 

Magnesium  is  next  to  iron  the  most  important  metallic 
constituent  of  meteorites.  It  occurs  always  in  the  com- 
bined form,  chiefly  as  a  constituent  of  chrysolite  and  the 
pyroxenes. 

Manganese  occurs  in  small  quantity  in  the  stone  meteorites 
and  in  traces  in  the  iron  meteorites.  In  the  iron  meteorites 
it  probably  occurs  alloyed  with  the  nickel-iron  as  a  metal. 
In  the  stone  meteorites  as  MnO  it  is  found  both  in  those 
portions  soluble  and  those  insoluble  in  HC1,  or,  in  other 
words,  both  in  chrysolite  and  the  pyroxenes.  Its  quantity 
rarely  exceeds  I  per  cent. 

Nickel  is  like  iron  a  constant  and  characteristic  ingredient 
of  meteorites.  As  a  metal  it  forms  with  iron,  cobalt,  and 
copper  the  alloy  called  nickel-iron  which  constitutes  the 
larger  part  of  the  iron  meteorites  and  is  also  abundant  in 
stone  meteorites.  Nickel  takes  part  with  iron  in  the  forma- 


COMPOSITION   OF   METEORITES  115 

tion  of  phosphides,  carbides,  and  oxides  and  less  prominently 
of  sulphides  and  chlorides.  From  the  silicates  of  meteorites 
it  seems  to  be  lacking  for  the  most  part,  thus  presenting  a 
contrast  to  terrestrial  silicates  (chrysolite  and  the  pyroxenes) 
which  frequently  contain  an  appreciable  quantity. 

Nitrogen  forms  a  small  percentage,  usually  less  than  one 
per  cent,  of  the  gases  found  in  meteorites.  Its  occurrence 
as  an  ammoniacal  compound  in  some  of  the  carbonaceous 
meteorites  is  also  probable. 

Oxygen  occurs  chiefly  as  a  constituent  of  the  siliceous 
minerals  of  meteorites.  It  also  takes  part  in  the  forma- 
tion of  the  oxides  such  as  chromite  and  magnetite  found  in 
minor  quantities  in  iron  meteorites.  It  is  not  found  among 
the  gases  of  meteorites. 

Palladium  has  appeared  as  traces  in  one  or  two  iron 
meteorites. 

Phosphorus  occurs  chiefly  in  the  form  of  schreibersite,  a 
phosphide  of  iron,  nickel,  and  cobalt.  It  is  never  lacking 
from  the  iron  meteorites  and  is  usually  found  in  small 
quantity  in  the  stone  meteorites.  Evidence  has  also  been 
obtained  of  its  occurrence  in  a  free  state  in  one  stone  mete- 
orite. 

Platinum  occurs  alloyed  with  nickel-iron.  It  is  found  only 
as  traces  or  a  few  hundredths  of  a  per  cent. 

Potassium  occurs  as  an  ingredient  of  the  feldspars  and 
may  also  take  part  in  the  constitution  of  some  of  the  py- 
roxenes. 

Radium  has  been  found  in  a  single  stone  meteorite,  that 
of  Dhurmsala*  in  the  quantity  of  1.12  x  io~12  per  gramme. 
Two  iron  meteorites  tested  at  the  same  time  showed  none. 

Ruthenium  occurs  alloyed  with  nickel-iron.  It  is  found 
only  in  traces. 

Silicon  forms  with  oxygen  and  the  metals  the  silicates 
of  which  the  stony  meteorites  are  chiefly  made  up.  With 
carbon  it  forms  the  rare  carbide  moissanite,  and  may  be 
wholly  present  in  this  form  in  the  iron  meteorites  or  in  part 
as  a  metal  forming  an  alloy. 

Sodium  occurs  like  potassium   as   an   ingredient  of  the 

*Strutt,  Proc.  Roy.  Soc.,  1906,  A,  77,  480. 


116  METEORITES 

feldspars  and  perhaps  also  of  some  of  the  pyroxenes.  It  is 
more  abundant  than  potassium. 

Sulphur  occurs  combined  with  iron,  nickel,  cobalt,  and 
calcium.  It  also  enters  into  the  composition  of  a  class 
of  hydrocarbons  found  in  meteorites.  It  is  more  abundant 
in  the  stone  than  in  the  iron  meteorites  but  is  quite  generally 
present  in  both. 

Tin  has  been  reported  only  in  minute  quantity  and  usually 
in  the  irons.  It  is  probably  alloyed  with  the  nickel-iron. 

Titanium  has  often  been  reported  to  the  extent  of  a  frac- 
tion of  one  per  cent  in  the  stone  meteorites,  usually  in  the 
insoluble  portion  and  therefore  believed  probably  to  occur 
in  the  pyroxenes.  Of  the  Angra  dos  Reis  meteorite,  which 
is  composed  almost  wholly  of  pyroxene,  Ti02  constitutes 
2.39  per  cent. 

Vanadium  occurs  as  traces  in  the  stone  meteorites,  prob- 
ably, according  to  Apjohn,  who  found  it  in  the  Limerick 
meteorite,  as  an  oxide  associated  with  chromite,  this  being 
characteristic  of  its  occurrence  in  terrestrial  rocks. 

Several  other  elements  have  been  reported  as  occurring  in 
meteorites,  but  the  occurrence  needs  confirmation.  Among 
these  are  arsenic,  antimony,  and  zinc.  Gold  was  described 
by  Liversidge  as  occurring  in  minute  yellow  grains  insoluble 
in  nitric  acid  in  the  irons  of  Boogaldi  and  Narraburra.* 
Several  elements  have  been  observed  in  the  spectroscopic 
examination  of  meteorites  which  have  not  been  recognized 
by  chemical  analysis.  Among  these  are  barium  and  stron- 
tium, lead  and  bismuth."); 

It  will  be  seen  from  an  examination  of  the  list  of  elements 
most  abundant  in  meteorites  that  they  are  of  low  atomic 
weight.  Oxygen,  silicon,  aluminum,  magnesium,  calcium, 
sulphur,  nickel,  and  iron  are  the  most  abundant  elements  and 
all  have  an  atomic  weight  below  60.  Platinum  and  iridium, 
the  two  heaviest  elements,  occur  in  but  minute  quantity. 

MINERALS 

The  following  minerals  grouped  according  to  Dana's 
system  have  been  satisfactorily  identified  in  meteorites: 

*Jour.  Roy.  Soc.  New  South  Wales,  1903,  37,  241. 
fLockyer.     The  Meteoritic  Hypothesis,  1890,  59. 


COMPOSITION   OF   METEORITES 


117 


Diamond 

C 

Isometric 

Elements 

Graphite 

C 

Hexagonal 

L  Nickel-iron 

Fe,  Ni,  Co,  Cu 

Isometric 

Kamacite 

Fe14  Ni 

Isometric 

Taenite 

Fe.  Ni, 

Plessite 

Fe.  Niw 

Oldhamite 

CaS 

Isometric 

Osbornite 

Oxysulphide  of 

Sulphides 

Ca  and  Ti 

Phosphides 

Pyrrhotite 

FeS 

Hexagonal 

and 

Daubreelite 

"FeS.  Cr2S3 

Carbides 

Schreibersite 

(Fe,  Ni,  Co)3P 

Tetragonal 

Cohenite 

Fe3C 

Isometric 

Moissanite 

SiC 

Hexagonal 

Chlorides        Lawrencite 

FeCl2 

Quartz 

Si02 

Hexagonal 

Oxides 

Tridymite 

SiO2 

f  Hexagonal  or 
}  Orthorhombic 

Magnetite 

Fe304 

Isometric 

Chromite 

(Fe,  Mg)  Cr2  O4 

Isometric 

Carbonates    Breunnerite       (Mg,  Fe)  CO3       Rhombohedral 

111        •       1  YYl  1  >  a  /vl  Ol3  v_yg          r-p   •    |« 

lagioclase  ^     \\   <?•   r\         Inclmic 

[  n  Ca  A12  Si3  O8 

Maskelynite 

Enstatite  Mg  Si  O3  Orthorhombic 

Hypersthene    (Fe,  Mg)  Si  O3     Orthorhombic 
Clinoenstatite  Mg  Si  O3  Monoclinic 

Clinohypher- 

Silicates        J      sthene  (Fe,  Mg)  Si  O3      Monoclinic 

Diopside  Mg  Ca  (Si  O3)2     Monoclinic 

Hedenbergite   (Mg,  Fe)  Ca 

(SiO3)2  Monoclinic 

w(Mg,  Fe)  Ca(Si 

03)2 
n(Mg,  Fe)  (Al, 

Fe)2SiO6          Monoclinic 


Augite 


118  METEORITES 

Weinber-         f  Na  Al  Si  O4 

Silicates  gerite  ' 3  Fe  Si  °3  Orthorhombic 

Forsterite          Mg2  Si  O4  Orthorhombic 

Chrysolite         (Mg,  Fe)2  Si  O4    Orthorhombic 

/  A  f  (Ca[F,  Cl]  ) 

Phosphates     Apatite  X    ,r>r\  \  u  i 

(Ca4(PO4)3  Hexagonal 

Of  the  above  minerals  nickel-iron,  chrysolite,  and  the 
pyroxenes  are  by  far  the  most  abundant.  Schreibersite, 
daubreelite,  oldhamite,  moissanite,  maskelynite,  and  wein- 
bergerite  are  minerals  which  have  not  as  yet  been  recognized 
terrestrially;  the  others  are  similar  to  terrestrial  minerals. 
A  fuller  account  of  the  above  minerals  follows. 

DIAMOND 

The  first  discovery  of  diamond  in  meteorites  was  made 
by  two  Russian  mineralogists,  JerofejefF  and  Satschinoff,* 
who  in  1888  found  in  the  Russian  meteorite  of  Nowo-Urei 
about  I  per  cent  of  small,  grayish  grains  whose  hardness, 
specific  gravity,  chemical  composition,  and  appearance 
under  the  microscope  all  corresponded  with  those  of  dia- 
mond. The  remainder  of  the  meteorite  was  composed  of 
chrysolite,  augite,  carbonaceous  matter,  and  nickel-iron. 
Some  of  the  properties  of  the  grains  considered  as  diamond 
which  led  to  their  determination  were  their  insolubility  in 
hydrochloric,  sulphuric,  and  hydrofluoric  acids  and  in  aqua 
regia;  their  being  unaffected  by  fusion  with  soda  or  acid 
potassium  sulphate,  and  their  combustibility  in  a  stream  of 
oxygen.  The  specific  gravity  of  the  grains  was  between 
2.89  and  3.3;  hardness  greater  than  that  of  corundum. 
By  analysis  0.0124  gram  of  these  grains  gave:  Carbon, 
95.40;  hydrogen,  3.23;  ash,  3.23;  total,  101.86.  If  the 
estimate  that  I  per  cent  of  the  meteorite  was  diamond  was 
correct,  the  total  amount  of  diamond  in  the  meteorite  was 
17.62  grams  or  85.43  carats.  The  grains  were  of  micro- 
scopic size  and  no  definite  crystal  forms  could  be  observed. 
Kunz  and  Lewisf  verified  the  observations  of  JerofejefF  and 

*Verh.  d.  russ.  min.  Gesell.  1888,  2,  24,  272-292.  Also  Comptes  Rendus  1888, 
1 06,  1679-1681. 

fScience,  1888,  u,  118-119. 


COMPOSITION   OF   METEORITES  119 

Satschinoff  to  the  extent  of  finding  a  substance  in  the 
Nowo-Urei  meteorite  which  abraded  sapphire.  The  next 
important  discovery  of  diamond  in  meteorites  was  made 
by  Foote  and  Koenig*  in  one  of  the  Canyon  Diablo  irons. 
In  cutting  one  of  these  irons  for  study  a  cavity  was  opened 
which  contained  small  black  grains  that  "cut  through 
polished  corundum  as  easily  as  a  knife  through  gypsum." 
These  grains  were  all  small  and  black  except  one  which  was 
white  and  about  }4.  mm.  (l/60  of  an  inch)  in  size.  This 
unfortunately  was  lost  in  manipulation.  The  grains  were 
regarded  as  diamonds  because  of  their  hardness  and  their 
indifference  to  chemical  reagents.  Later  Kunz  and  Hunt- 
ingtonf  by  dissolving  portions  of  several  Canyon  Diablo 
meteorites  obtained  white  grains  having  the  appearance  of 
beach  sand  which  were  unaffected  by  hydrofluoric  or  other 
acids.  With  these  they  succeeded  in  polishing  a  diamond 
by  the  methods  usually  employed  by  diamond  cutters. 
Soon  after,  HuntingtonJ  found  a  vein  in  one  of  the  Canyon 
Diablo  irons  which  contained  pyrrhotite,  silica,  and  amor- 
phous carbon  and  from  this  he  was  able  to  isolate  some 
transparent,  colorless  diamond  crystals  showing  the  forms 
of  octahedrons  and  hexoctahedrons.  About  y£  carat  of 
colorless,  yellow,  blue,  and  black  diamonds  were  thus  ob- 
tained by  Huntington. 

Mallard,§  who  also  investigated  the  Canyon  Diablo  dia- 
monds, found  in  a  hollow  of  one  of  the  irons  a  soft,  black, 
carbonaceous  substance  in  which  were  round,  black  grains 
from  ]4.  to  i  mm.  in  size,  which  had  sufficient  hardness  to 
scratch  the  cleavage  surface  of  a  colorless  diamond.  Friedel|  | 
obtained  from  one  of  the  irons  brownish-gray  grains  0.5  to 
0.8  mm.  in  size,  resembling  carbonado.  These  had  a  spe- 
cific gravity  of  3.3  and  o.oi  56  grams  and  yielded  on  analysis  : 

C  =  99.36 
Fe2Q3=   1.28 


100.64 

*Am.  Jour.  Sci.,  1891,  3,  42,  415-417. 
fAm.  Jour.  Sci.,  1893,  3,  470-473. 
JProc.  Am.  Acad.  Sci.,  1894,  29,  204-211. 
§Comptes  Rendus,  1892,  114,  812-814. 
||Bull.  Soc.  Franc.  Min.,  1892,  15,  258-263. 


120  METEORITES 

Later,  small,  transparent,  and  colorless  diamond  grains  were 
found  by  Friedel  in  Canyon  Diablo.  Moissan*  obtained 
by  solution  of  a  fragment  of  Canyon  Diablo  weighing  4 
grams,  three  forms  of  carbon,  (i)  dust-like,  carbonaceous 
particles,  (2)  rounded,  compact  fragments,  and  (3)  crumpled, 
thin  particles  of  brownish  color.  After  treatment  of  this 
mixture  with  boiling  sulphuric  and  hydrofluoric  acids  and 
potassium  chlorate,  two  yellowish,  bort-like  fragments  were 
obtained  which  had  the  hardness  of  diamond.  Later,| 
Moissan  dissolved  a  mass  of  the  Canyon  Diablo  iron  weigh- 
ing 53  kgs.  (116  pounds)  in  hydrochloric  acid  and  obtained 
about  800  grams  of  carbonaceous  residue.  In  this  he  found 
diamond,  both  as  very  small,  black,  rounded  grains,  and 
as  transparent,  drop-shaped  or  rounded  octahedral  forms. 
Derby}  and  Cohen§  both  examined  specimens  of  Canyon 
Diablo  for  diamonds  without  success.  Both  used  for  the 
tests  complete  individuals  weighing  about  200  grams  each 
which  they  dissolved  in  dilute  HC1.  The  residues  obtained 
were  completely  soluble  in  stronger  acids.  These  tests  show 
that  diamond  is  not  uniformly  distributed  through  the  Can- 
yon Diablo  meteorites.  Where  it  occurs  it  is  found  to  be 
most  abundant  near  nodules.  In  Carcote,  a  crystalline 
chondrite,  Sandberger||  found  dull  black  grains,  hardness  9, 
not  affected  by  acids,  which  he  regarded  as  weathered  carbo- 
nado. Weinschenk^f  found  in  the  residue  of  Magura  which 
was  insoluble  in  acids,  colorless  grains  and  splinters  partly 
isotropic  and  partly  doubly  refracting  which  scratched 
ruby  and  gave  CO2  on  burning.  The  presence  of  diamond 
in  this  meteorite  was  thus  indicated.  No  other  meteorites 
have  been  reported  to  contain  diamonds.  Moissan0  exam- 
ined Kendall  Co.,  Dehesa,  and  Toluca  for  diamond  without 
success.  The  Ovifak  iron  likewise  yielded  negative  results 
to  the  investigations  of  Moissan  and  Cohen.  By  seeking 

*Comptes  Rendus,  1893,  116,  218-224  and  288-290. 
fComptes  Rendus,  1904,  139,  773-780. 
JAm.  Jour.  Sci.,  1895,  3,  49,  108. 

§Meteoreisenstudien,  xi,  A.  N.  H.  Wien,  1900,  15,  374. 
||Neues  Jahrb     1889,  2,  180. 
TIAnn.  Wien  Mus.,  1889,  4,  99-100. 
°Comptes  Rendus,  1895,  131,  483-486. 


COMPOSITION   OF   METEORITES  121 

to  reproduce  experimentally  the  conditions  under  which 
diamonds  seemed  to  have  been  formed  in  the  Canyon  Di- 
ablo meteorites,  Moissan*  was  able  to  produce  artificial  dia- 
monds. Moissan's  method  consisted  in  strongly  compress- 
ing pure  sugar  charcoal  in  a  cylinder  of  soft  iron  and  closing 
this  by  a  plug  of  the  same  metal.  This  he  placed  in  a 
crucible  containing  about  200  grams  of  molten  iron,  melted 
it  by  means  of  an  electric  furnace,  withdrew  the  crucible 
at  once  from  the  furnace  and  cooled  it  as  rapidly  as  possible. 
The  object  of  the  sudden  cooling  was  to  form  a  crust  on 
the  mass  so  as  to  exert  a  pressure  on  the  interior  as  the 
latter  cooled,  since  iron,  like  water,  expands  as  it  solidifies. 
Water  may  be  employed  as  a  cooling  medium  but  owing  to 
the  formation  of  a  badly  conducting  layer  of  steam,  immer- 
sion in  molten  lead  for  cooling  purposes  was  found  to  be 
preferable.  After  cooling,  the  iron  was  dissolved  in  hydro- 
chloric acid  and  a  residue  consisting  of  graphite,  a  maroon- 
colored  variety  of  carbon,  carbonado,  and  diamond  was 
obtained.  This  residue  was  treated  with  aqua  regia,  hot 
sulphuric  acid,  hydrofluoric  acid,  potassium  chlorate,  and 
fuming  nitric  acid  and  the  residues  then  left  were  treated 
with  liquids  of  different  densities  to  separate  them.  From 
a  separation  with  bromoform,  small  fragments  having  the 
form,  hardness,  luster,  and  chemical  composition  of  diamond 
were  obtained.  Pure,  limpid  diamonds  in  some  cases  were 
found  which  reached  a  diameter  of  0.5  mm. 

Analogous  to  this  discovery  it  may  be  noted  that  micro- 
scopic diamonds  were  found  in  several  hard  steels  by  Rossel.f 
It  may  also  be  noted  that  the  stone  meteorites  which  con- 
tain diamonds  have  a  composition  similar  to  that  of  the 
peridotites  in  which  the  South  African  diamonds  are  found. 
Carbon  in  graphitic  cubic  form  was  noted  by  Haidinger  and 
Partsch  in  the  Magura  meteorite{  and  regarded  by  them  as 
a  pseudomorph  after  pyrite,  especially  as  planes  believed  to 
be  those  of  the  pentagonal  dodecahedron  were  observed. 
Rose§  later  suggested  an  origin  of  the  cubes  from  diamond 

*Comptes  Rendus,  1893,  116,  218-224,  and  1894,  118,  320-326. 

fComptes  Rendus,  1897,  123,  113. 

JPogg.  Ann.,  1846,  67,  437-439- 

§Abh.  Berlin  Akad.,  1863,  40  and  1872,  532-533. 


122  METEORITES 

and  showed  by  experiment  that  diamond  heated  out  of  con- 
tact with  air  becomes  opaque  and  of  graphitic  appearance. 
The  cubes  from  Magura  were  described  more  fully  later  by 
Brezina,*  who  stated  that  they  reached  a  size  of  2.5  mm. 
The  planes  were  somewhat  arched  and  the  solid  angles 
rounded.  Planes  of  the  dodecahedron  and  tetrakishexahe- 
dron,  the  latter  having  the  symbols  310  and  320,  were  found 
modifying  the  crystals.  The  carbon  of  which  they  were 
composed  was  partly  earthy  and  grayish-black  in  color  and 
partly  foliated  and  of  shining  metallic  luster.  The  scales 
of  the  latter  variety  showed  an  arrangement  parallel  to  the 
three  axes  of  a  cube. 

Similar  cubes,  though  smaller,  were  isolated  in  large 
numbers  by  Fletcherf  from  the  Youndegin  meteorite  and 
called  by  him  cliftonite  in  honor  of  R.  B.  Clifton,  pro- 
fessor of  physics  at  Oxford.  These  were  grayish-black, 
opaque  crystals  averaging  ^4  mm.  in  thickness,  having  a 
predominant  cubic  form  which  was  modified  occasionally 
by  the  dodecahedron  and  a  tetrakishexahedron.  Rounded 
and  depressed  planes  were  also  observed.  Some  individuals 
were  found  to  be  hollow,  others  to  have  a  shelly  structure. 
No  cleavage  was  discernible.  Hardness  was  2.5;  specific 
gravity  2.12;  streak  black.  The  chemical  characters  agreed 
completely  with  those  of  graphite.  Fletcher  regarded  the 
crystals  as  a  distinct  form  of  carbon  deserving  the  rank  of 
a  new  species,  but  the  weight  of  opinion  at  the  present  time 
tends  to  consider  them  as  pseudomorphs  after  diamond, 
for  which  the  name  cliftonite  can  be  conveniently  retained. 
Rose's  experiments,  which  as  previously  remarked  showed 
that  diamond  can  be  completely  converted  to  a  graphitic 
form  like  that  of  cliftonite  by  continued  heating  out  of 
contact  with  air,  makes  this  origin  seem  more  probable. 
Rose  found  that  the  high  temperature  of  the  electric  furnace 
was  necessary  for  the  change,  the  temperature  at  which 
cast  iron  melts  having  no  effect.  Cliftonite  was  also 
observed  by  Fletcher  in  the  iron  of  Cosby  Creek.  Hunt- 
ingtonf  found  cliftonite  in  Smithville  in  the  forms  of 

*A.  N.  H.  Wien,  1889,  4,  102-106. 
fMin.  Mag.,  1887,  7,  124-130. 
jProc.  Am.  Acad.  Sci.,  1894,  29,  255. 


COMPOSITION   OF   METEORITES  123 

cubo-octahedrons,  unmodified  cubes,  and  cubes  truncated 
by  the  dodecahedron  and  a  very  obtuse  tetrakishexahedron. 
He  also  found  a  skeleton  octahedron  of  graphite  ^  of  an 
inch  in  diameter  in  a  nodule  of  graphite  from  Cosby  Creek. 
Cohen  and  Weinschenk*  found  cliftonite  in  Toluca  in  the 
form  of  elongated  groups  composed  mostly  of  cubes  but 
occasionally  containing  octahedrons.  The  largest  crystals 
reached  a  size  of  only  o.i  mm.  They  oxidized  somewhat 
more  slowly  to  graphitic  oxide  by  treatment  with  potassium 
chlorate  and  nitric  acid  than  graphite  from  the  same  meteor- 
ite. With  the  exception  of  Toluca,  cliftonite  seems  to  be 
confined  to  the  coarse  octahedral  irons. 

GRAPHITE 

This  substance  occurs  in  grains  of  sufficient  size  for 
ready  examination  only  in  the  meteoric  irons.  In  these  it 
is  usually  in  the  form  of  nodules  but  sometimes  occurs  in 
plates  or  grains.  The  nodules  often  reach  considerable 
size.  One  nodule  taken  from  the  Cosby  Creek  iron  is  as 
large  as  a  small  pear  and  weighs  92  grams.  Even  larger 
ones  were  found  in  the  Magura  iron.  Toluca,  Cranbourne, 
Chulafmnee  and  Mazapil  are  other  irons  which  contain 
considerable  graphite.  Graphite  has  been  estimated  to 
form  1.17  per  cent  of  the  mass  of  Magura  and  0.8  per  cent 
of  the  Cosby  Creek  iron.  The  mineral  is  usually  associated 
with  iron  sulphide.  With  this  it  may  be  intimately  inter- 
grown  or  the  one  may  enclose  the  other.  Its  texture  is 
compact  rather  than  foliated.  Smith  found  that  the  mete- 
oritic  graphite  oxidized  much  more  rapidly  than  terrestrial 
graphite  on  treatment  with  nitric  acid  and  chlorate  of 
potash.  This  feature  distinguishes  it  from  the  amorphous 
carbon  separated  from  cast  iron.  The  meteoritic  graphite 
is  also  very  pure.  Although  occurring  in  nodules  of  the  size 
described,  which  must  have  segregated  from  the  surrounding 
mass,  the  ash  amounted,  in  an  analysis  made  by  Smith,  to 
only  i  per  cent.  By  ether  was  extracted  a  small  quantity 
of  a  substance  made  up  of  sulphur  and  a  hydro-carbon, 
which  constituted  the  only  other  impurity.  Emphasizing 

*Meteoreisenstudien,  A.  N.  H.  Wien,  1891,  6,  140-141. 


124  METEORITES 

the  differences  between  meteoritic  and  terrestrial  graphite 
Smith  was  inclined  to  believe  that  the  graphite  of  meteorites 
must  have  been  formed  by  the  action  of  bi-sulphide  of  car- 
bon upon  incandescent  iron  rather  than  that  it  was  analo- 
gous in  its  origin  to  terrestrial  graphite.  Ansdell  and  Dewar, 
however,  concluded  from  elaborate  comparisons  of  meteoritic 
and  terrestrial  graphite  that  they  were  similar  in  origin,  and 
were  formed  by  the  action  of  water,  gases,  and  other  agents 

on  metal  carbides. 

> 

AMORPHOUS  CARBON 

Meteorites  of  the  group  known  as  carbonaceous  meteor- 
ites, as  well  as  some  others,  are  permeated  by  a  dull-black, 
pulverulent  coloring  matter  which  is  usually  left  as  a  residue 
on  treatment  of  the  meteorite  with  acid.  This  residue 
sometimes  amounts  to  from  2  to  4.5  per  cent  of  the  mass. 

A  residue  similar  in  character  though  smaller  in  amount 
is  likewise  found  after  dissolving  many  of  the  iron  meteorites. 
These  residues  on  being  heated  in  air,  glow,  usually  become 
lighter  in  color  and  give  off  carbon  dioxide.  They  must 
therefore  be  considered  practically  pure  carbon. 

Berzelius  and  Wohler  believed  this  carbon  to  have  origi- 
nated, so  far  as  the  carbonaceous  meteorites  are  concerned, 
from  the  decomposition  of  the  hydrocarbons  of  the  latter. 
In  this  respect  they  regarded  it  analogous  to  terrestrial 
humus,  though  of  very  different  origin.  Smith  considered 
it  similar  in  origin  to  the  graphite  of  iron  meteorites  and 
Weinschenk  believes  it  similar  to  one  of  the  forms  of  carbon 
produced  in  the  making  of  cast  iron.  No  indications  that 
it  had  an  organic  origin  have  ever  been  discovered. 

NICKEL-IRON 

Nickel-iron  is  the  substance  of  which  the  metallic  portion 
of  meteorites  is  chiefly  composed.  The  iron  meteorites 
consist  of  it  almost  wholly  and  from  the  stone  meteorites 
it  is  perhaps  never  altogether  absent,  although  Roda, 
Chassigny,  Shalka,  and  Angra  dos  Reis  have  been  described 
as  without  it.  In  the  carbonaceous  meteorites  it  is  not 
present  as  such  but  their  oxidation  products  indicate  that 


COMPOSITION   OF   METEORITES  125 

it  occurred  in  them.  From  this  almost  universal  presence 
of  nickel-iron  in  meteorites,  Bombicci  has  argued  that  the 
magnetism  of  meteorites  is  the  property  by  virtue  of  which 
they  are  drawn  to  the  earth,  the  latter  acting  as  a  magnet 
to  attract  them. 

In  composition  the  nickel-iron  of  meteorites  is  not  a  sub- 
stance of  fixed  proportions  but  an  alloy  of  iron  and  nickel 
in  which  the  percentage  of  nickel  lies  between  6  and  20  per 
cent,  and  for  the  most  part  below  II  per  cent.  In  the  stone 
meteorites  the  percentage  of  nickel  is  sometimes  higher. 
Thus  in  the  nickel-iron  of  Honolulu,  Mordvinovka,  Nerft, 
and  Middlesbrough  percentages  of  nickel  of  37.73,  21.16, 
20.94,  and  23.01  per  cent,  respectively,  have  been  reported. 

Accompanying  the  nickel  of  nickel-iron,  cobalt  and  cop- 
per seem  to  be  universally  present.  The  percentages  of 
cobalt  vary  as  a  rule  between  0.5  and  2.5  per  cent  (in  Uri- 
coechea  2.56  per  cent).  Those  of  copper  range  from  traces 
to  a  few  tenths  of  one  per  cent.  The  percentages  of  cobalt 
or  copper  seem  to  hold  no  definite  relation  to  the  amount 
of  nickel,  although  irons  rich  in  nickel  are  usually  corre- 
spondingly rich  in  cobalt. 

The  color  of  nickel-iron  varies  from  iron-gray  or  steel- 
gray  in  alloys  poor  in  nickel,  to  tin-white  and  silver-white 
in  those  rich  in  nickel.  Under  the  microscope  in  reflected 
light,  nickel-iron  exhibits  a  bluish  reflection. 

Nickel-iron  is  more  or  less  easily  soluble  in  the  common 
cold,  dilute  acids,  also  in  solutions  of  copper  sulphate,  copper 
chloride,  copper  ammonium  chloride,  mercurous  chloride, 
bromine  water,  and  iodine  with  potassium  iodide.  By 
cold,  dilute  hydrochloric  acid  (i  HC1 :  20  aq.)  the  nickel-poor 
alloys  are  completely  and  the  nickel-rich  partly  dissolved. 

The  specific  gravity  of  nickel-iron  varies  chiefly  between 
7.6  and  7.9,  although  determinations  as  low  as  6.5  and  as 
high  as  8.1  have  been  reported.  Normally  it  should  be 
higher  the  greater  the  percentage  of  nickel  since  while  the 
specific  gravity  of  pure  iron  is  7.88  that  of  pure  nickel  is  8.8. 

In  cohesive  properties  nickel-iron  varies  considerably, 
being  now  hard,  now  soft,  now  tensile,  now  brittle,  now 
malleable,  and  now  non-malleable.  Of  52  iron  meteorites 


126  METEORITES 

accounts  of  which  were  collected  by  Cohen,  48  were  reported 
to  be  malleable  and  4  not  malleable.  The  malleability  of 
much  nickel-iron  is  attested  by  the  fact  that  it  has  been 
manufactured  both  by  barbarous  and  civilized  peoples  into 
utensils  and  ornaments  such  as  knives,  spearheads,  horse- 
shoes, nails,  and  rings.  In  boring  and  cutting  iron  meteor- 
ites very  different  qualities  are  exhibited  by  different  indi- 
viduals, some  yielding  easily  to  tools  and  others  only  with 
difficulty.  These  differences  may  be  due  to  variations  in 
the  quality  of  the  nickel-iron  itself  or  more  often  probably 
to  the  presence  of  harder  minerals,  such  as  cohenite  and 
diamond.  The  iron  of  Canyon  Diablo  shows  great  resist- 
ance to  tools,  due  undoubtedly  to  included  diamond. 

All  nickel-iron  seems  to  take  a  good  polish.  It  is  also 
magnetic  and  many  iron  meteorites  show  polarity  acquired 
probably  by  induction  from  the  earth.  The  location  of 
the  magnetic  poles  has  been  determined  near  the  ends  of 
individuals  of  Staunton,  Welland,  Tonganoxie,  Bingera, 
and  Imilac. 

The  nickel-iron  of  meteorites  is  as  a  rule  quite  compact. 
Fletcher  describes  cavities  bounded  by  planes  (negative 
crystals)  in  the  meteorite  of  Greenbrier  County,  and  in  Lick 
Creek  portions  possessed  a  porous  character.  Of  the  iron 
meteorites  nickel-iron  forms  the  entire  substance  without 
regular  boundaries  except  as  octahedral  or  cubic  cleavage 
may  appear.  In  the  iron-stone  meteorites  it  may  appear 
either  as  a  network  the  meshes  of  which  are  filled  with 
silicates  (pallasites),  or  as  apparently  rounded  grains  united 
by  threads,  or  as  branching  threads  filling  spaces  between 
the  silicates  (mesosiderites).  In  the  chondritic  meteorites 
nickel-iron  takes  the  form  of  isolated  grains  or  variously 
shaped,  often  toothed  flakes  filling  the  spaces  between  the 
silicates.  Regular  forms  more  or  less  resembling  crystals 
are  occasionally  observed.  Siemaschko  described  crystals 
from  Tabory  weighing  0.2  grams  showing  the  combina- 
tion 100,  in,  no,  and  hko.  Incomplete  cubes  with  vicinal 
faces  of  a  tetrakishexahedron  have  been  described  from 
Barbotan  by  Partsch  and  Pfahler.  Goalpara  furnished 
cubelike  crystals  according  to  Tschermak,  and  Tomatlan 


COMPOSITION   OF   METEORITES  127 

octahedrons  according  to  Shepard.  Wohler  described  six 
and  four-sided  forms  from  Parnallee  which  he  interpreted  as 
fragments  of  a  dodecahedron.  Brezina  noted  crystals  of 
nickel-iron  in  the  druses  of  Estherville. 

Besides  crystals  nickel-iron  occurs  in  rounded  forms 
resembling  chondri.  Such  forms  observed  in  Hainholz 
reached  a  diameter  of  22  mm.  (i  inch)  and  in  Mincy  6  cm. 
(2^/2  inches).  Of  other  chondri  nickel-iron  often  constitutes 
a  large  part.  In  these  it  takes  the  form  of  flakes,  foliae, 
grains,  and  cuboidal  forms  having  at  times  a  concentric 
arrangement.  Such  chondri  have  been  noted  in  Renazzo. 
Meso-Madarasz,  Borkut,  Dhurmsala,  Gopalpur,  and  Tie- 
schitz.  In  many  of  the  siliceous  chondri  of  stone  meteor- 
ites nickel-iron  often  forms  a  periphery  either  as  separate 
grains  or  as  a  thin,  coherent,  irregular  cover.  In  Parnallee 
a  cylinder  of  nickel-iron  was  observed  of  the  dimensions 
I  x  y^  mm.  In  several  of  the  stone  meteorites  films  and 
scales  of  nickel-iron  occur,  appearing  in  section  as  fine 
metallic  veins. 

Although  the  nickel-iron  of  meteorites  appears  in  a  pol- 
ished piece  to  be  a  homogeneous  substance  of  uniform 
composition,  investigation  shows  that  it  is  in  reality  a  com- 
plex substance,  made  up  of  alloys  containing  different 
quantities  of  nickel.  The  existence  and  character  of  these 
alloys  is  easily  made  evident  by  subjecting  a  polished  sur- 
face of  the  nickel-iron  to  the  action  of  heat,  acids,  or  other 
etching  agent.  Figures  of  a  more  or  less  banded  character 
then  appear  on  the  surface  of  the  iron  showing  its  complex 
structure.  The  discovery  of  this  means  of  investigating 
the  character  of  nickel-iron  was  made,  as  has  previously 
been  mentioned,  by  Alois  von  Widmanstatten  of  Vienna  in 
1808.  The  production  of  these  figures  by  heating  can  be 
accomplished  by  placing  a  thin  section  of  the  meteorite 
upon  an  asbestos  plate  and  placing  it  over  a  Bunsen  burner. 
According  to  the  degree  of  oxidation  the  different  alloys 
then  appear  in  different  colors,  as  for  instance  blue,  purple, 
and  yellow.  Although  this  was  the  method  first  employed 
by  Widmanstatten  it  is  rarely  used  at  the  present  time  since 
the  employment  of  liquid  etching  agents  is  simpler  and 


128  METEORITES 

gives  more  delicate  results.  Of  these  agents  the  most  con- 
venient and  satisfactory  is  usually  nitric  acid.  For  pre- 
liminary testing  the  acid  diluted  to  about  one-tenth  its 
normal  strength  may  be  applied  to  a  small,  flat,  freshly 
filed  surface  of  the  nickel-iron.  In  four  or  five  minutes  the 
character  of  the  figures  will  usually  be  roughly  outlined. 

For  etching  of  a  plate  for  careful  study  of  the  figures  more 
pains  should  be  taken.  Meteorites  differ  in  the  degree  and 
speed  with  which  they  are  attacked,  some  etching  easily 
and  quickly  with  weak  acid,  others  only  after  longer  treat- 
ment with  stronger  acid.  The  surface  of  the  meteorite  to  be 
investigated  should  be  flat  and  smooth  and  the  larger  the 
surface  the  greater  will  be  the  opportunity  afforded  to  study 
the  details  of  its  structure.  Foote  Mineral  Company  of 
Philadelphia,  who  have  had  excellent  success  in  etching 
meteorites,  have  given  the  writer  the  following  details  of 
their  method  of  etching: 

1.  Wash  the  specimen  with  benzine. 

2.  Lacquer  the  unpolished  back  and  edges  with  a  lacquer 
known  as  "steel  gloss,"  diluting  it  about  one-half  with  ben- 
zine.    When  this  side  is  dry,  carefully  remove  with  benzine 
any  lacquer  which  may  have  run  over  the  edges  onto  the 
polished  surface.     An  electric  fan  greatly  hastens  the  drying 
of  the  lacquer. 

3.  Lacquer   any   nodules.     They   should   be   completely 
covered,  as  they  are  readily  attacked  by  the  acid,  and  will 
stain  the  etched  surface. 

4.  Place  the  iron  so  that  the  polished  surface  is  horizontal. 
Wash  with  a  5  to  15  per  cent  solution  of  C.  P.  nitric  acid 
for  from  15  seconds  to  4  or  5  minutes,  until  the  etching  is 
brilliant.     If  etched    much   longer,   the   iron   will   darken. 
When  the  surface  begins  to  get  rough,  the  maximum  bril- 
liancy has  been  reached.     The  acid  should  be  kept  as  thick 
and  as  even  as  possible  by  rubbing  the  plate  with  a  large 
brush.     As  the  acid  becomes  discolored,  it  should  be  brushed 
off  and  fresh  acid  added. 

5.  To  clean  and  facilitate  rapid  drying,  quickly  put  the 
section  into  clean  warm  water  (120°  to  130°  F.)  for  several 
minutes,  rubbing  with  a  brush. 


COMPOSITION   OF   METEORITES  129 

6.  Dry  in  a  few  seconds  with  blotting-paper. 

7.  Thickly  lacquer  the  etched  surface  at  once.     To  avoid 
oxidizing,   the  operations   from  4  to  7   should   be   accom- 
plished as  quickly  as  is  practicable,  by  having  all  materials 
at  hand. 

Where  possible  the  writer  has  found  the  etching  to  be 
more  delicately  performed  if  the  plate  to  be  etched  is  dipped 
into  the  acid  with  the  side  to  be  etched  down  instead  of 
up  and  instead  of  pouring  the  acid  on  the  plate.  Such 
dipping  facilitates  removal  by  gravity  of  the  products  of 
etching.  Nevertheless,  in  many  instances  the  size  and 
shape  of  the  plate  prevent  such  immersion  and  the  acid  must 
be  poured  on.  Other  etching  agents  besides  nitric  acid 
which  may  be  employed  are  dilute  hydrochloric  acid,  the 
addition  to  which  of  a  small  volume  of  choride  of  antimony 
is  said  to  lessen  subsequent  rusting,  a  solution  of  sulphate 
of  copper,  the  deposited  copper  being  removed  by  ammonia, 
solutions  of  chloride  of  mercury,  chloride  of  gold,  chloride 
of  platinum,  fused  alkalies  or  bromine  water.  The  figures 
obtained  with  some  of  these  agents  are  said  to  differ  from 
those  obtained  in  other  ways. 

Upon  the  great  majority  of  iron  meteorites  the  figures 
which  appear  upon  etching  show  the  nickel-iron  to  be  made 
up  of  three  different  alloys  differing  in  form,  color,  luster, 
and  degree  of  solubility.  One  of  these  alloys  appears  as 
bands  of  iron-gray  color  and  dull  luster,  which  on  heating 
are  more  thickly  covered  with  oxide  or  on  etching  are  more 
depressed  than  the  other  alloys.  The  bands  cross  each 
other  in  manifold  fashion,  and  while  rather  uniform  in  width 
in  any  single  meteorite  in  different  meteorites  show  varia- 
tions in  width  from  X  to  2  mm.  and  in  length  from  a  few 
millimeters  up  to  10  cm.  (2^  inches).  This  alloy  was  called 
by  Reichenbach  Balkeneisen  or  Kamazit  from  /ea/^af,  a  pole 
or  shaft,  and  is  known  in  English  as  kamacite.  Bordering 
the  bands  of  kamacite  appear  others  which  are  narrower, 
silver-white  in  color  and  more  brilliant  in  luster.  Their 
substance  is  less  attacked  by  acids  or  oxidizing  agents  and 
hence  they  stand  out  in  relief.  To  this  alloy  the  name 
Bandeisen  or  Taenit  from  raivLa,  a  ribbon,  was  given  by 


130  METEORITES 

Reichenbach.  These  two  alloys  run  parallel  to  and  adjoin- 
ing each  other  and  together  form  what  is  known  as  a  lamella. 
The  crossing  of  these  lamellae  in  network  fashion  leaves 
angular  spaces  or  meshes  which  are  often  filled  by  a  third 
alloy  generally  of  darker  color  and  duller  luster  than  the 
kamacite.  This  third  alloy  is  known  as  plessite  from 
ReichenbacrTs  name  Plessit  or  Fiilleisen.  Its  degree  of  ox- 
idation and  solubility  is  intermediate  between  that  of  kam- 
acite and  taenite.  The  three  alloys  together  are  known 
as  the  trias  or  triad. 

Meteorites  containing  or  made  up  of  nickel-iron  which 
exhibit  these  three  alloys  are  known  as  octahedral  meteor- 
ites or  octahedrites  since  the  arrangement  of  the  lamellae 
in  such  meteorites  proves  to  be  parallel  to  the  planes  of  an 
octahedron.  Two  other  classes  of  iron  meteorites  as  already 
noted  display  no  such  compound  structure.  These  are  the 
hexahedrites  or  cubic  meteorites  and  ataxites  or  meteorites 
without  structure.  The  hexahedrites  are  made  up  of  but  a 
single  one  of  the  above  alloys,  kamacite,  while  the  ataxites 
have  a  diverse  composition. 

KAMACITE 

Balkeneisen 

Kamacite  is  the  predominant  constituent  of  nickel-iron. 
Of  the  cubic  iron  meteorites  and  some  of  the  ataxites  it 
forms  practically  the  entire  mass  and  in  the  octahedral 
meteorites  it  is  more  abundant  than  any  other  constituent. 
In  color  it  is  iron-gray  as  contrasted  to  the  tin-white  of 
taenite  and  the  usually  darker  gray  of  plessite.  It  is  solu- 
ble in  dilute  acids  of  the  stronger  class  such  as  HC1  1:20 
and  very  slowly  even  in  acetic  acid.  Its  specific  gravity 
ranges  from  7.78  to  7.87  and  its  hardness  is  between  4  and  5. 

According  to  structure,  three  different  kinds  of  kamacite 
are  recognized:  hatched,  spotted,  and  granular.  The 
hatched  kamacite  (Brezina's  schraffirten  Kamazit,  Reichen- 
bach's  Feilhiebe)  is  characterized  by  being  covered  by 
networks  of  fine  lines  tending  to  cross  at  right  angles.  These 
are  like  the  Neumann  lines  of  the  cubic  meteorites  on  a 
smaller  scale.  The  spotted  kamacite  (Brezina's  fleckig 


COMPOSITION   OF   METEORITES  131 

Kamazit)  shows  varying  dark  and  light  spots  from  unequal 
reflections  of  light.  The  appearance  is  caused  by  groups  of 
lines  or  pits.  The  spots  are  of  irregular  outline  and  rarely 
exceed  I  mm.  in  diameter.  The  granular  kamacite  (Bre- 
zina's kornige  or  abgekornt  Kamazit)  consists  of  grains 
separated  by  rather  deep  channels.  This  separation  usually 
appears  only  after  strong  etching.  The  grains  may  be  coarse 
(i  to  2  mm.  diameter)  or  fine  (o.i  to  I  mm.  diameter.) 

All  these  kinds  of  kamacite  may  be  found  in  different 
meteorites.  The  cubic  meteorites  are  composed  almost 
wholly  of  hatched  kamacite  and  some  of  the  ataxites  almost 
wholly  of  granular  kamacite.  The  other  kinds  of  kamacite 
are  seen  in  the  bands  of  different  octahedral  meteorites. 

Several  kinds  of  kamacite  are  also  distinguished  according 
to  their  position  or  form.  These  kinds  are  known  as  swath- 
ing kamacite,  swollen  kamacite,  grouped  kamacite,  and  un- 
equally grouped  kamacite.  Swathing  kamacite  (Brezina's 
Wickelkamazite,  Reichenbach's  Fiilleisen  or  Wulsteisen) 
is  seen  enclosing  accessory  constituents  in  meteoric  irons. 
It  usually  forms  a  band  two  or  three  millimeters  broad 
around  accessory  minerals,  following  their  outlines  within 
and  not  conforming  to  the  general  structure  of  the  meteorite 
without.  Swollen  kamacite  (Brezina's  wulstiger  Kamazit) 
is  a  characteristic  form  assumed  by  the  kamacite  bands  of 
many  of  the  octahedral  meteorites.  Such  bands  are  short, 
swollen  in  the  middle,  and  often  have  rounded  ends  bounded 
by  taenite.  Grouped  kamacite  (Brezina's  gescharter  Kama- 
zit) consists  of  bands  lying  close  together,  parallel  and  gen- 
erally elongated.  It  characterizes  many  octahedral  meteor- 
ites. Unequally  grouped  kamacite  (Brezina's  ungleich 
gescharter  Kamazit)  consists  of  grouped  bands  of  different 
lengths,  of  which  the  middle  ones  are  usually  the  longer. 
Such  bands  may  be  seen  in  many  octahedral  meteorites. 

In  addition  to  these  forms  of  kamacite,  certain  jagged 
and  angular  fragments  found  remaining  behind  after  the 
solution  in  dilute  HC1  of  the  kamacite  of  many  octahedral 
meteorites  prove  on  analysis  to  have  a  composition  near 
that  of  kamacite.  Their  lower  solubility  is  believed  to  be 
generally  due  to  included  schreibersite  or  cohenite. 


132  METEORITES 

All  the  above-named  forms  of  kamacite  have  a  chemical 
composition  closely  approximating  that  represented  by  the 
formula  FeH  Ni  of  which  the  percentages  are  Fe  93.11  per 
cent,  Ni+Co  =  6.89  per  cent=  100. 

Analyses  of  kamacite  of  the  various  kinds  mentioned  are 
given  below,  the  kamacite  of  octahedral  irons  being  given 
first,  as  it  was  in  these  that  kamacite  was  first  distinguished. 

ANALYSES  OF  KAMACITE 

I.  Kamacite  of  octahedral  meteorites. 

Fe  Ni  Co  Cu  C         Total  Fe  :  Ni  +  Co 

i 93-Qi         6.22        0.77          tr.  100  13.98:1 

2 93-09        6.69        0.25         0.02         100.05  14.09:1 

REFERENCES 

1.  Bendego.     Isolated  by  Derby,  analyzed  by  Florence  and  Dafert:   Ann.  Mus. 
Rio  de  Janeiro,  1896,  ix,  140  and  183.     Calculated  to  100  after  deducting  insoluble 
residue. 

2.  Welland.     Davison:  Am.  Jour.  Sci.,  1891   (3),  xlii,  64.      Plates  i  to  2  mm. 
thick,  of  the  color  of  cast-iron,  with  wrinkled  surface  and  covered  with  a  thin  layer 
of  magnetite;  brittle;  conchoidal  fracture. 

II.  Swathing  kamacite. 

Fe  Ni  Co  Total  Fe  :  Ni+Co 

92.62  6.55  0.83  loo-  13.19:1 

REFERENCE 
Glorieta.     Cohen  and  Weinschenk:   A.  N.  H.  Wien,  1891,  vi,  158. 

III.  Jagged,  residual  kamacite. 

Fe  Ni  Co  Cu            C  Total  Fe  :  Ni+Co 

i 92.62  6,81  0.57  100  13.19  i 

2 93-01  6.25  0.74  100  13.98  i 

3 93-27  6.04  0.64  ....         0.05  100  14.67  i 

4 93-89  5.30  0.61  ....        0.20  100  16.69  i 

5 94-05  5.26  0.57  ....        0.12  loo  16.95  i 

6 94-09  5.51  ....  0.05        0.34  100  17.77  i 

REFERENCES 

1.  Canyon  Diablo.     Florence:  Am.  Jour.  Sci.,  1895  (3),  xlix,  104.      Calculated 
to  IOO  after  deducting  0.31  per  cent  taenite  and  0.35  per  cent  schrcibersite. 

2.  Magura.     Sjostrom:    A.  N.   H.  Wien,  1898,  xiii,  484.     Calculated  to  100 
after  deducting  0.58  per  cent  schreibersite. 

3.  Magura.     Manteuffel:  A.  N.  H.  Wien,  1892,  vii,  156. 

4.  Staunton.     Manteuffel:   A.  N.  H.  Wien,  1892,  vii,  157. 

5.  Toluca.     Manteuffel:   A.  N.  H.  Wien,  1892,  vii,  157. 

6.  Canyon  Diablo.     Florence:  Am.  Jour.  Sci.,  1895  (3),  xlix,  104.     Calculated 
to  loo  after  deducting  0.31  per  cent  taenite  and  0.35  per  cent  schreibersite. 


COMPOSITION   OF   METEORITES  133 

IV.  Angular,  residual  kamacite. 

Fe  Ni  Co  Total  Fe  :  Ni+C. 

92.94  6.18  0.88  100  13.83:1 

REFERENCE 

Magura.     Cohen  and  Weinschenk:   A.  N.  H.  Wien,  1891,  vi,  152. 

TAENITE 

Bandeisen,  Meteorin,  Edmondsonite. 

Taenite  is  the  ingredient  of  octahedral  nickel-irons  which 
occurs  in  thin  plates.  These  are  usually  of  a  nickel-white 
color  though  they  become  by  oxidation  golden  to  isabel- 
yellow.  They  border  the  kamacite  bands  and  containing 
more  nickel  are  less  attacked  by  etching  agents.  They, 
therefore,  stand  in  relief.  The  thickness  of  the  taenite 
plates  may  vary  from  0.03  to  0.25  mm.  Taenite  is  less  liable 
to  decomposition  than  kamacite,  and  hence  often  remains  in 
the  form  of  bright,  more  or  less  elastic  plates  after  the 
decomposition  of  the  mass  of  a  meteorite.  These  plates" 
often  have  a  crumpled,  wavy  appearance.  They  resemble 
schreibersite,  for  which  they  have  sometimes  been  mistaken, 
in  being  strongly  magnetic  but  fuse  with  more  difficulty 
B.B.  Taenite  is  attacked  slowly  by  cold,  dilute  acids  and  con- 
siderably but  not  entirely  dissolved.  Concentrated  nitric 
and  hydrochloric  acids  and  copper-ammonium  chloride 
dissolve  it  completely.  Analyses  of  taenite  'show  per- 
centages of  nickel  varying  from  about  13  to  48  per  cent, 
cobalt  being  also  usually  reported  in  quantity  up  to  2  per 
cent.  These  analyses  indicate  that  taenite  has  not  a 
uniform  composition.  S.  W.  J.  Smith*  has  observed  that 
taenite  isolated  mechanically  usually  contains  less  nickel 
than  that  isolated  chemically  through  the  prolonged  action 
of  dilute  acid,  and  states  that  this  indicates  that  taenite 
contains  considerable  kamacite  which  is  dissolved  out  by 
the  acid.  The  analyses  given  below  do  not  bear  out  this 
statement  however  since  the  percentage  of  nickel  seems  to 
be  entirely  independent  of  the  manner  in  which  the  mate- 
rial for  analysis  was  obtained. 

*Phil.  Trans.  London,  1908,  Ser.  A.,  vol.  208,  p.  21. 


134 


METEORITES 


Furthermore  the  structure  of  the  taenite  bands  indicates 
a  complex  composition.  Tschermak  found  the  taenite 
lamellae  of  Ilimae  to  consist  of  a  fine  network  of  different 
bodies  which  he  regarded  as  chiefly  nickel-iron  mixed  with 
pure  iron.  Taenite  occurs  only  in  the  octahedral  irons 
and  more  abundantly  in  the  fine  octahedrites  than  in  the 
coarse.  Thus  Cohen*  estimated  the  percentage  of  taenite  in 
the  coarse  octahedrite  of  Wichita  as  2.64  per  cent,  while  in 
the  medium  octahedrites  Toluca  and  Misteca  he  regarded 
it  as  6.79  per  cent  and  6.75  per  cent,  respectively,  and  in 
the  fine  octahedrites  Chupaderos  and  Glorieta  Mountain 
10.24  Per  cent  and  n-35  Per  cent. 

The  composition  of  taenite  as  shown  by  various  analyses 
is  as  follows : 

ANALYSES  OF  TAENITE 


Fe 

Ni+Co 

Fe 

Ni 

Co        Cu 

C 

Total 

+  Cu 

i 

86 

4.4. 

1*1     O2 

O    Z± 

IOO 

oo 

6 

•  9 

2  

8c 

T'T 

oo 

j.  j  .  \s& 

14  .OO 

qq 

oo 

6 

4" 

'3-- 

•    •    •          ^j 

...     85 

oo 

A  if.        v-"-f 

15  .OO 

V  :/ 
IOO 

oo 

6 

.  o 

4. 

83 

28 

16.68     ....     0.04 

IOO 

oo 

c 

.  2 



.    .   .          wj 

...     80 

30 

19.60     

99 

90 

J 

4 

.   I 

6. 

...     74 

78 

24.32 

0.33     •••• 

0.50 

99 

93 

3 

.  2 

7  

-•  •     73 

IO 

23-63 

2.10       

1.17 

IOO 

00 

3 

.  0 

8  

-  •  •     73 

o 

27.00 

100 

00 

2 

.  8 

9  

...     72 

12 

27-73 

0  .  02       .... 

0.  12 

IOO 

00 

2 

•  7 

10  

...     71 

29 

26.73 

1.68     .... 

0.30 

IOO 

00 

2 

.6 

ii  

...     70 

H 

29.74 

99 

88 

2 

.  5 

12  

...     69 

30 

29  73 

o  .  60     .... 

0-37 

IOO 

00 

2 

•  4 

13  

...     68 

1*3 

30.85 

0.69    0.33 

....        IOO.OO 

2 

.  2 

14  

...     65 

54 

32-87 

1.59     .... 

IOO 

oo 

2 

.  O 

IS  

...     65 

39 

33-20 

1.41 

IOO 

oo 

2 

.  O 

16  

...65 

26 

34  34 

o  .  40     .... 

IOO 

oo 

2 

.  0 

17  

...63 

55 

34  65 

i.  oi     0.30 

o  49 

IOO 

oo 

•  9 

18  

...     63 

04 

35-53 

1.43    .... 

tr. 

IOO 

00 

.  8 

10 

...     61 

89 

36.95 

0.36     .... 

0.80 

IOO 

00 

•  7 

*  7  

20  

...     61 

87 

38.13     ....       tr. 

IOO 

00 

•  7 

21  

•  ...     57 

18 

34  oo 

0-55 

91 

•73 

•  7 

22  

.  .  .  .     50 

73 

47.80 

0.63     0.37 

0.47 

IOO 

.00 

•  i 

REFERENCES 

i.  Cosby  Creek.  Reichenbach,  Jr.:  Pogg.  Ann.,  1861,  xciv,  258.  Plates 
8  cm.  long  and  2^  cm.  broad,  mechanically  isolated  by  Reichenbach,  Sr.  Mean 
of  three  analyses. 

*Meteoreisenstudien,  ii,  A.  N.  H.  Wien,  1892,  vii,  160,  161. 


COMPOSITION   OF   METEORITES  135 

2.  Charcas.  Meunier:  Ann.  Chim.  et  Phys.,  1869  (4),  xvii,  31.  Particles 
mechanically  isolated  by  their  color. 

.     3.    Caille.     Meunier:   Ann.  Chim.  et  Phys.,  1869  (4),  xvii,  32.     Net-like  web, 
isolated  by  means  of  dilute  nitric  acid. 

4.  Casas  Grandes.     Tassin:    Proc.  U.  S.  Nat.  Mus.,  1902,  xxv,  73. 

5.  Kenton  Co.     Nichols:   Pub.  Field  Col.  Mus.,  1902,  Geol.  Ser.,  i,  315.    Thin, 
tin-white,  elastic  magnetic  plates,  4  mm.  square,  with  finely  ribbed  surface. 

6.  Welland.     Davison:     Am.    Jour.    Sci.,    1891    (3),    xlii,    66.     Mechanically 
isolated    plates     jVVo   mrn-    thick,    silver-white   to   bronze-yellow,    flexible    and 
elastic. 

7.  Staunton.     Cohen   and  Weinschenk:    Ann.  Wien  Naturhist.  Mus.,   1891, 
vi,  146.     Gray,  relatively  thick  and  brittle  plates.     Isolated  by  dilute  HC1.     Cal- 
culated to  100  after  deducting  schreibersite. 

8.  Cosby  Creek.     Smith:   Comptes  Rendu,  1881,  xcii,  843.     Little  thin  plates 
of  white  metallic  color  left  after  dissolving  the  iron  in  acid. ' 

9.  Canyon  Diablo.     Tassin:    Smithsonian  Misc.  Coll.,  1907,  i,  212.     Calcu- 
lated to  100  after  deducting  0.26  per  cent  schreibersite. 

10.  Magura.     Weinschenk:   Ann.  Wien  Naturhist.  Mus.,  1889,  iv,  97.     Thin, 
tough,  silver-white  lamellae  soluble  with  difficulty  in  acids.     Isolated  by  dilute 
HC1.     Calculated  to  100  after  deduction  of  schreibersite. 

11.  Cranbourne.     Flight:    Phil.  Trans.  London,  1882,  No.  171,  888.     White, 
flexible,  magnetic,  triangular  or  rhombic  mechanically  isolated  plates. 

12.  Misteca.     Cohen:   Ann.  Wien  Naturhist.  Mus.,  1892,  vii,  152.     Dull  and 
brittle  plates.     Isolated  by  HC1.     Calculated  to  100  after  deducting  schreibersite. 

13.  Canyon  Diablo.     Florence:    Am.  Jour.  Sci.,   1895   (3),  xlix,   105.     Thin 
tin-white,  flexible  plates.     Calculated  to   100  after  deduction  of  3.60  per  cent 
schreibersite. 

14.  Wichita  Co.     Cohen  and  Weinschenk:   Ann.  Wien  Naturhist.  Mus.,  1891, 
vi,  155.     Isolated  by  dilute  HC1.     Calculated  to  100  after  deduction  of  schreiber- 
site. 

15.  Chupaderos.     ManteufFel:    Ann.  Wien  Naturhist.  Mus.,   1892,  vii,   150. 
Brittle,  tin-white  plates.     Isolated  by  HC1.     Calculated  to  100  after  deducting 
schreibersite. 

16.  Toluca.     Cohen  and  Weinschenk:   Ann.  Wien  Naturhist.  Mus.,  1891,  vi, 
137.     Tin-white,    flexible   plates.     Isolated    by    HC1.     Calculated    to    100   after 
deducting  schreibersite. 

17.  Canyon  Diablo.     Fahrenhorst:  Ann.  Wien  Naturhist.  Mus.,  1900,  xv,  376. 
Thin,  flexible  plates  partly  appearing  made  up  of  many  lamellae,  light-yellow  or 
grayish.     Schreibersite,  2.34  per  cent  deducted. 

18.  Glorieta  Mountain.     Cohen  and  Weinschenk:  Ann.  Wien  Naturhist.  Mus., 
1891,  vi,  137.     Tin-white,  flexible,  grouped  plates.     Isolated  by  HC1.     Calculated 
to  100  after  deducting  schreibersite. 

19.  Bischtiibe.     Cohen:    Ann.  Wien  Naturhist.  Mus.,  1897,  xii,  54.     Large, 
flexible  plates  with  included  schreibersite.     Isolated  by  HC1. 

20.  Penkarring  Rock.     Fletcher:    Min.  Mag.,  1899,  xii,  174.     Thin,  flexible 
plates.     Analysis  calculated  to  100  after  deducting  4.18  per  cent  schreibersite. 

21.  Medwedewa.     Berzelius:     Pogg.    Ann.,    1833,    xxxiii,    133.     Analysis    of 
skeleton  material  left  behind  after  dissolving  in  HC1. 

22.  Beaconsfield.     Sjostrom:    Monatsberichte  Berlin  Akad.,  1897,  1041.  Tinto 
silver-white,  lustrous  plates.     Iron  determined  by  difference. 

The  analyses,  as  will  be  observed,  show  variations  of 
composition  from  Fe7Ni  to  FeNi.  While  this  variation  is  a 
wide  one  it  is  evident  that  it  is  between  certain  limits,  and 
that  it  would  be  incorrect  to  ascribe  too  indefinite  a  com- 
position to  taenite. 


136  METEORITES 

PLESSITE 

Fulleisen 

The  term  plessite  or  fulleisen  was  applied  by  Reichenbach 
to  the  nickel-iron  alloy  filling  the  spaces  or  fields  between 
the  lamellae  of  octahedral  meteorites,  and  the  term  is  still 
used  in  this  sense.  This  alloy  is  usually  of  darker  color  and 
duller  luster  than  kamacite,  and  as  a  rule  is  surrounded  by 
a  border  of  taenite.  The  amount  of  plessite  occurring  in 
this  way  varies  in  different  irons.  When  the  fields  are  more 
abundant  than  the  lamelFae,  plessite  is  correspondingly  more 
abundant,  but  in  some  irons  there  is  an  almost  complete 
absence  of  fields  and  therefore  of  plessite.  In  some  of  the 
finely  laminated  octahedrites,  as  Butler,  there  are  no  dis- 
tinguishable fields  but  plessite  forms  the  principal  mass  of 
the  meteorite  with  octahedral  lamellae  scattered  through  it 
either  singly  or  in  bundles.  In  several  pallasites  also  pies- 
site  strongly  predominates.  While  plessite  thus  appears  to 
have  a  certain  individuality,  a  little  examination  of  it  with 
a  lens  or  even  the  naked  eye,  especially  as  it  occurs  in  the 
fields  of  octahedral  meteorites,  shows  that  it  is  not  a  homo- 
geneous substance.  Often  the  fields  show  a  structure  which 
simply  repeats  that  of  the  rest  of  the  meteorite  on  a  smaller 
scale.  The  plessite  is  in  these  cases  made  up  of  kamacite 
and  taenite  perhaps  less  perfectly  separated  than  in  the 
larger  lamellae.  Davison*  carefully  separated  by  hand- 
picking  the  two  constituents  of  this  character  making  up 
the  fields  of  the  Welland  meteorite  and  found  that  they  cor- 
responded both  physically  and  in  chemical  composition  to 
the  kamacite  and  taenite  of  the  same  meteorite.  The  kam- 
acitic  portion  of  the  plessite  was  made  up  of  minute  rods 
T/6  to  T/3  mm.  in  diameter  and  the  taenitic  portion  of  bands 
I/i3o  to  J/22o  mm.  thick.  It  is  evident  from  all  these  consid- 
erations that  much  plessite  represents  simply  less  individ- 
ualized portions  of  the  meteorites  in  which  it  occurs  and  its 
composition  would  therefore  correspond  in  general  to  that 
of  the  meteorite  itself.  Its  composition  may  therefore  be 
safely  considered  as  intermediate  between  that  of  kamacite 

*Am.  Jour.  Sci.,  1891,  3,  42,  65. 


COMPOSITION   OF   METEORITES  137 

and  taenite,  or  between  Fei4Ni  and  FeNi.  From  analogies 
with  the  behavior  of  other  alloys  it  has  been  suggested  by 
Fletcher*  that  the  behavior  of  these  nickel-iron  alloys  may 
be  illustrated  by  that  of  a  fused  mixture  of  silver  and  cop- 
per. When  the  percentage  by  weight  of  silver  is  72,  and 
that  of  copper  28,  says  Fletcher,  solidification  begins,  not 
at  a  temperature  between  960°  and  1083°,  the  solidifying 
temperatures  of  silver  and  copper,  respectively,  but  at  a 
temperature  below  both,  namely  770°.  The  solid  which 
first  separates  has  the  same  percentage  composition  as  the 
original  mixture;  the  part  still  fused  has  thus  itself  the  same 
•percentage  composition  as  before,  and  continues  to  solidify 
at  the  same  temperature,  and  in  the  same  way,  until  the 
solidification  is  complete.  Such  a  mixture,  having  a  definite 
composition  and  a  definite  temperature  of  solidification,  was 
for  a  time  regarded  as  a  definite  chemical  compound  with 
a  complex  chemical  formula,  but  on  microscopic  examina- 
tion the  resultant  solid  was  found  to  be  heterogeneous; 
minute  particles  of  the  silver  and  copper  were  seen  to  lie 
side  by  side,  the  particles  being  granular  or  lamellar  in  form 
according  to  the  circumstances  of  the  cooling.  If  the  per- 
centage of  silver  is  different  from  72,  whether  it  be  higher 
or  lower,  the  solidification  begins  at  a  higher  temperature 
than  770°;  whence  the  mixture  containing  72  per  cent  of  sil- 
ver has  been  conveniently  termed  eutectic  (i.e.,  very  fusible). 
When  the  silver  is  in  excess  of  72  per  cent,  the  excess  of 
silver  gradually  collects  together  and  solidifies  at  various 
parts  of  the  cooling  fused  mass;  the  still  fused  portion  thus 
gradually  becomes  poorer  in  that  metal,  and  the  tempera- 
ture, instead  of  remaining  constant,  gradually  falls  during 
the  separation  of  the  solid.  At  length  the  percentage  of 
silver  in  the  fused  portion  falls  to  72  per  cent  and  the  tem- 
perature to  770°;  the  solid  which  now  begins  to  form  is  no 
longer  pure  silver,  but  a  material  containing  72  per  cent  of 
that  metal;  and  it  continues  to  have  the  same  percentage 
composition  as  the  surrounding  liquid,  and  the  temperature 
of  solid  and  liquid  to  be  770°,  until  the  solidification  is  com- 

*Fletcher,  Introduction  to  the  Study  of  Meteorites.      British  Museum,  Nat. 
Hist.,  London,  1909,  p.  40. 


138  METEORITES 

plete.  The  final  solid  thus  consists  of  blebs  of  silver  scat- 
tered through  a  fine  groundmass  of  eutectic  mixture  of 
silver  and  copper.  Similarly,  if  the  copper  is  in  excess  of 
28  per  cent,  the  final  solid  consists  of  blebs  of  copper  scat- 
tered through  a  fine  groundmass  of  eutectic  mixture  of  silver 
and  copper.  Hence  Fletcher  suggests  that  plessite  is  a 
eutectic  of  nickel-iron,  and  that  the  kamacite  and  taenite 
first  separated  from  it.  Prof.  Rinne*  is  of  the  opinion, 
however,  that  separation  took  place  after  solidification. 
Hence  he  proposes  the  term  eutropic  instead  of  eutectic  as  it 
avoids  the  conception  of  fusion. 

It  is  evident  that  further  study  of  these  points  is  desirable. 
Experimental  investigation  should  show  whether  iron-nickel 
alloys  have  a  eutectic  and  if  so  the  composition  of  that 
eutectic.  According  to  the  different  development  of  taenite 
in  plessite  the  appearance  of  plessite  may  vary  from  a  dull, 
dark-gray  to  a  lighter-colored,  glittering  alloy.  In  some 
meteorites  also,  especially  the  pallasites,  plessite  may  have 
a  spotted  appearance  like  spotted  kamacite. 

OLDHAMITE 

This  is  a  simple  calcium  sulphide  which  has  been  found 
in  a  few  meteorites.  It  is  light  brown  in  color  and  trans- 
parent when  pure.  Hardness  4,  specific  gravity  2.58. 
It  is  soluble  in  water,  isotropic,  and  has  equal  cleavage  in 
three  directions,  hence  is  doubtless  isometric.  It  was  first 
discovered  by  Maskelyne  in  the  Bustee  meteorite,  occurring 
in  rounded  grains  coated  with  gypsum  through  alteration. 
He  gave  it  the  name  oldhamite  in  honor  of  R.  D.  Oldham, 
Director  of  the  India  Geol.  Survey.  The  mineral  was  found 
occurring  in  chestnut-brown  spherules  scattered  at  one  end 
of  the  meteorite.  These  spherules,  as  nearly  as  can  be 
determined  from  Flight's  figuref  range  from  6  mm.  in 
diameter  down.  The  composition  of  the  spherules  was 
determined  by  Maskelyne,  in  two  analyses,  I  and  II,  to  be 
the  following: 

*Neues  Jahrb.  fur  Min.,  1905,  Bd.  I,  122. 

fA  Chapter  in  the  History  of  Meteorites,  1887,  118. 


COMPOSITION   OF   METEORITES  139 

I  II 

Oldh       't    /  Calcium  monosulphide 89.369  90.244 

\  Magnesium  monosulphide 3  . 246  3  . 264 

Gypsum 3-951  4. 189 

Calcium  carbonate 3  .434            

Trolite 2 . 303 

100.  100. 

Oldhamite  was  observed  in  the  Hvittis  meteorite  by 
Borgstrom*  as  present  in  the  form  of  transparent  grains  3 
mm.  in  diameter  and  of  a  brownish  yellow  color.  The  min- 
eral was  isotropic  and  easily  dissolved,  with  evolution  of 
H2S,  by  acetic  acid.  Little  honey-yellow  grains  seen  in 
Bishopville  were  regarded  by  Maskelyne  as  oldhamite  and 
Brezina  saw  similar  ones  in  Aubres.  As  the  water  extract 
of  Morristown  contained  calcium  sulphide,  Merrillf  con- 
cluded that  oldhamite  was  present  in  that  meteorite.  Tas- 
sin  concluded^  from  an  analysis  of  the  non-magnetic  portion 
of  Allegan  that  oldhamite  occurred  in  that  meteorite  also, 
but  could  obtain  no  visible  evidence  of  its  presence.  Mer- 
rill also  observed  the  mineral  in  Indarch.  Oldhamite  is 
notable  in  being  a  meteoritic  mineral  which  has  not  yet 
been  discovered  terrestrially.  Vogt  observed  it  in  furnace 
slags.§ 

OSBORNITE 

In  the  brown  spherules  of  oldhamite  found  in  the  Bustee 
meteorite,  Maskelyne  observed  minute  octahedrons  having 
a  golden  color  and. luster.  1 1  They  were  not  affected  by  acids 
nor  by  fusion  with  potassium  carbonate.  Ignited  in  dry 
chlorine  they  glowed,  lost  their  metallic  luster  and  left  a 
deliquescent  residue.  Only  .002  of  a  grain  could  be  obtained 
for  analysis,  hence  only  qualitative  determinations  could  be 
made.  These  showed  the  presence  of  calcium,  sulphur,  and 
an  element  which  was  regarded  as  either  titanium  or  zir- 
conium. On  account  of  the  resistance  to  acids  which  the 
mineral  exhibited,  Maskelyne  thought  it  should  probably 

*Die  Meteoriten  von  Hvittis  and  Marjalahti,  Helsingfors,  1903,  35. 

fAm.  Jour.  Sci.,  1896,  4,  152-153. 

|Proc.  U.  S.  Nat.  Mus.,  1908,  34,  433-434. 

§Arch.  Math.  Nat.,  1890,  14,  72. 

||Phil.  Trans.,  1870,  109,  198-202. 


140  METEORITES 

be  regarded  as  an  oxysulphide  of  calcium  and  titanium  or  zir- 
conium rather  than  a  simple  sulphide.  He  named  the  min- 
eral osbornite  in  honor  of  Mr.  Osborne,  who  had  brought 
the  Bustee  meteorite  to  England  and  collected  information 
regarding  the  fall.  The  mineral  has  never  been  reported 
from  any  other  meteorite. 

PYRRHOTITE 

Troilite 

Iron  sulphide  was  early  recognized  as  a  constituent  of 
meteorites,  Count  Bournon  having  noted  it  in  several 
meteorites  in  1802.  He  regarded  it,  however,  as  pyrite. 
The  easy  decomposability  by  acids  of  the  meteoritic  iron 
sulphide  as  compared  with  pyrite  was  soon  noted,  however, 
and  the  sulphide  was  then  assumed  to  be  pyrrhotite,  especial- 
ly since  Rose  in  1825  found  crystals  in  Juvinas  which  gave 
forms  identical  with  those  of  pyrrhotite.  Several  later 
investigators  found  the  composition  of  the  iron  sulphide  of 
iron  meteorites  to  be  FeS,  thus  differing  from  that  of 
pyrrhotite  which  was  regarded  as  FenSi2.  Accordingly 
Haidingerin  1863*  proposed  the  name  troilite  for  the  simple 
iron  sulphide  of  meteorites,  a  name  given  in  honor  of  the 
Jesuit  priest,  Dominico  Troili,  who  had  described  in  1766 
the  Albareto  meteorite  and  mentioned  the  occurrence  of 
iron  sulphide  in  it.  Inasmuch  as  Rose's  measurements  indi- 
cated that  the  iron  sulphide  of  one  of  the  stone  meteorites 
was  pyrrhotite  while  analysis  gave  the  composition  of  the 
iron  sulphide  of  iron  meteorites  as  FeS,  it  was  for  some  time 
thought  that  the  iron  sulphide  of  stone  meteorites  should  be 
regarded  as  pyrrhotite  and  that  of  iron  meteorites  as  troilite. 
This  view  was  adopted  by  Cohenf  in  his  earlier  work  but 
modified  later.  MeunierJ  was  of  the  opinion  that  all  mete- 
oritic iron  sulphide  was  pyrrhotite,  and  adopted  for  pyr- 
rhotite the  formula  Fen  Si2.  Hintze§  considers  troilite  a 

*Sitzb.  Wien  Akad.,  xlvii,  II,  287-289. 
fMeteoritenkunde,  1894,  Heft  I,  190. 
JMeteorites,  Paris,  1884,  62. 
§Handbuch  der  Mineralogie,  630. 


COMPOSITION   OF   METEORITES  141 

synonym  for  pyrrhotite  but  gives  pyrrhotite  the  formula 
FeS. 

Analyses  show  no  essential  difference  between  the  iron 
sulphide  of  iron  and  stone  meteorites  and  according  to 
Busz*  the  measurements  upon  which  Rose  based  his  deter- 
mination of  the  crystal  form  of  the  Juvinas  troilite  were 
approximate  only  and  showed  great  variations. 

The  latest  work  upon  the  subject  has  been  that  of  Allen 
and  associates, f  who,  although  they  do  not  seem  to  have 
worked  upon  meteoritic  iron  sulphide  directly,  concluded 
from  an  elaborate  general  study  of  the  sulphides  of  iron 
that  troilite  should  not  be  considered  to  differ  mineralogic- 
ally  from  pyrrhotite,  it  being  simply  the  end  point  of  a 
series  of  solid  solutions.  The  larger  percentage  of  iron  in 
the  pyrrhotite  of  meteoritic  irons  as  compared  with  that  in 
terrestrial  pyrrhotite  they  regard  as  due  to  the  excess  of  iron 
present  at  the  time  of  formation  of  the  sulphide.  It  is 
thought  probable  by  them  that  the  pyrrhotite  of  stone  me- 
teorites does  not  contain  this  excess  of  iron.  It  may  be  de- 
sirable, therefore,  to  use  the  general  name  pyrrhotite  for 
the  iron  sulphide  of  meteorites  in  general,  and  that  plan  is 
here  adopted.  It  may  be  remarked  that  troilite  differs 
from  terrestrial  pyrrhotite  in  being  easily  decomposed  by 
acids,  in  leaving  no  residue  of  sulphur  after  such  decompo- 
sition, in  being  as  a  rule  non-magnetic,  and  in  having  a 
higher  specific  gravity  than  terrestrial  pyrrhotite. 

The  color  of  meteoritic  pyrrhotite  varies  from  bronze- 
yellow  to  tomback  brown,  the  darker  color  tending  to  be 
acquired  on  exposure.  Hardness  4,  specific  gravity  4.68- 
4.82.  Streak  grayish  black.  Luster  metallic.  Fuses  easily 
B.B.  to  a  black,  magnetic  globule.  Easily  decomposed  by 
hydrochloric  acid  with  evolution  of  hydrogen  sulphide. 
Crystal  form  as  determined  by  Rose  in  Juvinas  (Fig.  47) 
and  Brezina  in  Bolson  de  Mapimi,  hexagonal.  The  follow- 
ing forms  are  reported: 

o  (oooi),  r  (1010),  t  (1120),  s  (loll),  P  (2021),  v  (1121) 

Brezina  reports  cleavage  II  to  the  base  and  the  pyramidal 

*  Neues  Jahrbuch,  1895,  i,  125-6. 
fAm.  Jour.  Sci.,  1912,  4,  33,  213. 


142  METEORITES 

planes  P  (2021)  striated  II  to  the  base.  Linck  at  first 
concluded  from  the  cleavage  of  troilite  that  its  form  was 
isometric,  but  later*  regarded  the  form  as  like  that  of  pyr- 
rhotite.  Such  crystals  as  have  been  found  have  been  of 
small  size  and  with  imperfect,  rounded  faces.  They  occur 
in  druses  of  the  stone  meteorites.  Be- 
sides Juvinas  they  have  been  reported 
from  Richmond,  Farmington,  and 
Estherville.  Most  of  the  pyrrhotite  in 
stone  meteorites  occurs  in  the  form  of 
small,  scattered  grains  without  angular 
or  regular  outline.  These  grains  rarely 
reach  a  diameter  of  more  than  a  few 
r  VK~7; — L^"r  .  millimeters  although  Rose  reported  one 

tic.  47. —  Pyrrhotite      .     ^    ..       .  ...  ,,   . 

crystal     from     the    in  Gruneberg  1 3  mm.  in  diameter.    Vein- 
Juvinas  meteorite.     u'ke  masses   r  Cm.  long  have  also  been 

After  Rose.  -i      i        T        i         •         i  •  • 

described.  In  the  chondntic  meteorites 
pyrrhotite  is  especially  common  in  scattered  grains.  It  is 
frequently  intergrown  with  nickel-iron  in  all  proportions 
but  it  also  occurs  singly.  The  darker  color  and  dull  luster 
of  pyrrhotite  easily  distinguish  it  from  nickel-iron  and 
further  distinction  may  be  obtained  by  allowing  a  meteorite 
section  to  stand  a  few  minutes  in  a  solution  of  copper 
sulphate.  Copper  will  then  be  deposited  upon  the  nickel- 
iron  but  not  upon  the  pyrrhotite,  since  pyrrhotite  does  not 
reduce  copper  from  a  solution  of  copper  sulphate.  So  far 
as  has  been  observed,  the  distribution  of  the  pyrrhotite  in 
the  chondritic  meteorites  bears  no  especial  relation  to  the 
structure  of  the  chondri. 

In  the  iron  meteorites  pyrrhotite  is  common  and  abundant. 
It  especially  characterizes  the  medium  octahedrites,  and 
occurs  in  them  in  much  larger  masses  than  in  the  stone 
meteorites.  A  nodule  of  pyrrhotite  isolated  by  Smith  from 
Cosby  Creek  weighed  200  grams,  and  one  obtained  from 
Magura  was  13  centimeters  long.  Nodules  of  a  spheroidal 
form  are  a  common  mode  of  occurrence.  Other  common 
forms  are  cylindrical,  lens-shaped,  oval,  and  indented.  In 
certain  sections  a  ring-like  form  may  be  presented.  A  re- 

*Cohen,  Meteoritenkunde,  Heft  I,  1894,  191,  and  Heft  II,  1903,  248. 


COMPOSITION   OF  METEORITES  143 

markable  mode  of  occurrence  is  that  forming  the  so-called 
Reichenbach  lamellae  (Fig.  48).  These  are  small  plates  of 
pyrrhotite  distributed  through  the  nickel-iron  of  some  mete- 
orites and  oriented  according  to  the  planes  of  a  cube.  These 
lamellae  though  occasionally  larger,  range  as  a  rule  from 
0.1-0.2  mm.  in  thickness  and  from  1-3  cm.  in  length.  Staun- 


1 


>' 


FIG.  48. — •  Reichenbach  lamellae  as  seen  in  the  Ilimae  meteorite. 

ton,  Trenton,  Victoria  West,  Cleveland,  Merceditas,  and 
especially  Jewell  Hill  are  meteorites  which  exhibit  these 
lamellae.  The  lamellae  were  first  observed  by  Reichen- 
bach in  Lenarto  and  Caille.  Tschermak  noted  their 
orientation  parallel  to  the  three  planes  of  a  cube  in  the 
Ilimae  and  other  meteorites,*  and  Brezina  proposed  the 

*  Denkschrift  Wien  Akad.,  1871,  31,  192-4. 


144  METEORITES 

term  Reichenbach  lamellae*  by  which  they  are  now 
generally  known.  The  formation  of  Reichenbach  lamellae 
in  a  meteorite  must  occur  prior  to  that  of  the  nickel- 
iron.  Schreibersite  sometimes  borders  the  lamellae. 
Associated  with  large  nodules  of  pyrrhotite  other  min- 
erals are  frequently  found,  often  with  a  more  or  less  zonal 
arrangement.  Graphite  and  schreibersite  thus  frequently 


FIG.  49. —  An  iron  meteorite  of  the  Canyon  Diablo  fall  which  is  perforated  probably 
by  the  fusing  out  of  a  nodule  of  pyrrhotite.  The  weight  of  this  individual  is 
219  Ibs. 

join  with  pyrrhotite  and  occasionally  chromite  and 
daubreelite.  A  common  zonal  arrangement,  seen  especial- 
ly in  Wichita  and  Canyon  Diablo,  is  an  interior  of  pyr- 
rhotite surrounded  by  a  layer  of  graphite  and  that  by  one 
of  schreibersite  or  cohenite.  ' 

Pyrrhotite,  like  impurities  in  artificial  iron,  tends  to  be 
most  abundant  toward  the  periphery  of  a  meteoric  in- 
dividual. Owing  to  this  fact  and  its  easy  fusibility  it  may 
play  an  important  part  in  the  shaping  of  the  pittings  which 
characterize  the  surface  of  meteorites.  More  striking  still 
are  the  results  it  produces  when  an  entire  nodule  fuses  out 

*Denkschrift  Wien  Akad.,  1880,  43,  13-16. 


COMPOSITION   OF   METEORITES 


145 


and  leaves  a  hole  which  may  pass  entirely  through  an  iron 
meteorite.     (Fig.  49.) 

Most  of  the  analyses  of  meteoritic  pyrrhotite  show  a  close, 
approximation  to  the  formula  FeS  the  percentages  of  which 
are:  Fe  63.60,  S  36.40.  In  the  26  analyses  here  given  only 
three  depart  far  from  this  formula  and  these  standing  alone 
can  hardly  be  regarded  conclusive.  As  a  rule  the  quantity 
of  nickel,  cobalt,  or  copper  present  is  very  small.  Meteor- 
itic pyrrhotite  in  this  respect  therefore  differs  to  a  marked 
degree  from  schreibersite,  since  in  the  latter  nickel  and  co- 
balt are  essential  constituents. 

ANALYSES  OF  PYRRHOTITE 


i 

Fe 

6q    28 

Ni          Co 

Cu        Si02 

2 

64.    IQ 

O    I  3 

T. 

6^  03 

4 

5 

63.84 

63  82 

tr  

6 

8 
9 

10 

ii 

12 
13 

63.80 
63.61 
63.53 
63.48 
63.47 
63.41 
63-40 

63  .  3; 

0.42 

0  .  20          .... 

o  .  08       

H. 

J     J3 

63  .  34 

:i 

17 

18 

10 

63.28 
63.00 

62.65 
62.38 
62.32 

0-45        tr. 

I  .  02          .... 

I  .96 

0.32 
I    C8 

....       o  .  67 
tr.         0.56 

20 

.      •> 
62.21 

o  16      o  56 

21 

22 

23 
24 

11 

62.01 

61.80 
61  .  ii 
59-01 

58-94 
58.07 

0.89 
1.56 

0.14       .... 
0.42 
4-34       1-52 

tr  

Fe+Ni+Co 

S 

Total           +Cu  :  S 

34-72 

100 

0.929. 

35-68 

100 

0.969 

36.07 

100 

0.985 

36.16 

100 

o  .  989 

37-36 

101  .18 

i  .  023 

36.28 

100.08 

0-993 

36.33 

TOO.  12 

0.997 

36-05 

IOO 

0.986 

36.21 

99.69 

0.996 

35-89 

IOO 

0.988 

36.29 

99.70 

i 

36.21 

99.81 

0-993 

35-91 

99.26 

0.990 

36.66 

IOO 

I  .Oil 

35-59 

99-59 

0.976 

35-27 

99.96 

o  .  954 

35-39 

IOO 

0.958 

35-67 

99-01 

0.994 

36.  10 

IOO 

0.988 

35-05 

98.49 

0.977 

38.28 

101.18 

.  064 

36.64 

IOO 

.012 

39  56 

100.67 

•  H3 

40.03. 

99.18 

.  118 

39-99 

99-35 

.  118 

36.07 

IOO 

0.990 

"  REFERENCES 

1.  Bendego.     Dafert:    Ann.  Mus.  Nac.  Rio  de  Janeiro,  1896,  ix,  129.     After 
separation  of  5.26  per  cent  of  insoluble  residue,  consisting  chiefly  of  daubreelite 
and  schreibersite.     Traces  of  nickel,  cobalt  and  silica  were  found.     The  material 
analyzed  consisted  of  non-magnetic  particles  which  dissolved  without  evolution 
of  sulphur  in  moderately  concentrated  HC1. 

2.  Tennasilm.     Schilling:    Archiv.  fur  die  Naturk.  Liv.,  Esth.  u.  Kurlands, 
1882  (i),  ix, .109.     Calculated  to  100  after  deducting  0.357  per  cent  residue.     The 
lens  showed  an  admixture  of  nickel-iron. 


146  METEORITES 

3.  Rowton.  Flight:    Phil.  Tr.  London,  1882,  No.  171,  896.     Iron  determined 
by  difference. 

4.  Sokobanja.     Losanitsch:      Ber.  der  deutsche  Chem.  Gesell.  Berlin,  1878,  xi, 
97.     Copper  not  present.     Sulphur  determined  by  difference. 

5.  Nenntmannsdorf.     Geinitz:  Neues  Jahrbuch,  1876,  609-610. 

6.  Cosby  Creek.     Smith:   C.  R.,  1875,  Ixxxi,  978. 

7.  Cranbourne.     Flight:    Phil.  Tr.  London,  1882,  No.  171,  891.     Mean  of  4 
analyses  after  deduction  of  0.215  Per  cent  an(J  0.297  Per  cent  insoluble  residue, 
0.13  per  cent  chlorine  and  0.207  per  cent  sulphur. 

8.  Bear  Creek.     Smith:  Am.  Jour.  Sci.,  1867  (2),  xliii,  66.     Calculated  to  100 
after  deducting  1.81  per  cent  of  residue. 

9.  Cosby  Creek.     Smith:  C.  R.,  1875,  Ixxxi,  978. 

10.  Seelasgen.     Rammelsberg:  Monatsber.  Berlin  Akad.,  1864,  368.     Sulphur 
determined  by  difference,  0.64  per  cent  manganese. 

11.  Jelica.     Losanitsch:    Berichte  der  deutsche  Chem.  Gesell.  Berlin,   1892, 
xxv,  880.     No  nickel  or  cobalt. 

12.  Casas  Grandes.     Tassin:   Proc.  U.  S.  Nat.  Mus.,  1902,  xxv,  72.     Color  of 
material  analyzed  brass  to  bronze  yellow;  weakly  magnetic. 

13.  Seelasgen.  Rammelsberg:   Monatsber.  Berlin  Akad.,  1864,  368. 

14.  Sierra  de  Chaco.     Domeyko:   C.  R.,  1864,  Iviii,  555. 

15.  Bjurbole.     Borgstrom:    Bull.  Com.  Geol.  de  Finlande,  1902,  Nr.  12,  25. 
Mean  of  several  closely  agreeing  analyses. 

16.  Steinbach.      Winkler:     Nova  acte  Halle  Akademie,  1878,  xl,  No.  8,  357. 

17.  Cosby  Creek.     Rammelsberg:    Pogg.  Ann.,  1864,  cxxi,  367.     Calculated 
to  loo  after  deducting  0.74  per  cent  residue.     Sulphur  determined  by  difference. 

18.  Tazewell.     Smith:   Am.  Jour.  Sci.,  1855  (2),  xix,  156. 

19.  Seelasgen.     Rammelsberg:    Zeit.  der  deutsch.  geol.  Gesell.  Berlin,   1870, 
xxii,  894.     Sulphur  determined  by  difference.     Calculated  to  100  after  deducting 
0.18  per  cent  P. 

20.  Cosby  Creek.     Smith:   Am.  Jour.  Sci.,  1876  (3),  xi,  433.     Dissolved   by 
HNOs  from  a  nodule  of  graphite;  0.30  per  cent  MgO. 

21.  Nocoleche.     Cooksey:    Records  of  Australian  Museum,  Sydney,  1897,  iii, 
53.     The  material  analyzed  was  treated  with  mercuric  chloride  for  some  time  to 


remove  34.6  per  cent  intermingled  nickel-iron. 

22.    Cosby  Creek.     Rammelsberg:  Pogg.  Ann.,  1864,  cxxi,  367.     Calculate* 
loo  after  deducting  0.60  per  cent  residue.     Sulphur  determined  by  difference. 


23.  Danville.     Smith:  Am.  Jour.  Sci.,  1870  (2),  xlix,  91. 

24.  Toluca.     Meunier:  Ann.  Chim.  et  Phys.,  1869  (4),  xvii,  42. 

25.  Jelica.     Meunier:  Ann.  geol.  de  la  Pen.  Balkanique,  1893,  iv,  5-10. 

26.  Beaconsfield.     Sjostrom:     Sitzb.    Berlin    Akad.,    1897,    1044.     Material, 
separated  with  great  care,  consisted  of  non-magnetic  grains  ^-2  mm.  in  diameter. 
Graphite  0.33  per  cent,  traces  P  and  Cl. 

DAUBREELITE 

This  mineral,  originally  discovered  by  Smith  in  one  of  the 
Coahuila  irons*  is  an  iron-chromium  sulphide  peculiar  to 
meteorites.  Its  composition  is  FeS,  Cr2S3.  It  is  found 
in  nearly  all  the  cubic  iron  meteorites  and  has  also  been 
identified  in  theirons  of  Toluca,  Nelson  County,  Cranbourne, 
Canyon  Diablo  and  others.  It  has  never  been  found  in  stone 
meteorites.  It  usually  accompanies  pyrrhotite,  either  bor- 
dering nodules  or  crossing  them  in  veins.  Sometimes,  how- 

*Am.  Jour.  Sci.,  1876,  3,  12,  109;  1878,  3,  16,  270. 


COMPOSITION   OF   METEORITES  147 

ever,  it  occurs  as  thin  plates  or  grains.  It  is  black  in  color, 
has  a  black  streak,  is  of  metallic  luster,  brittle  and  not  mag- 
netic. It  is  infusible  before  the  blowpipe  and  becomes  mag- 
netic in  the  reducing  flame.  It  is  not  attacked  by  hot  or 
cold  hydrochloric  acid,  but  is  completely  dissolved  by  nitric 
acid  without  the  separation  of  free  sulphur.  This  solubility 
distinguishes  it  from  chromite.  Its  system  of  crystalliza- 
tion is  not  known  though  it  exhibits  rectangular  and  tri- 
angular partings  which  indicate  one  of  the  systems  of  high 
symmetry.  Sp.  gr.  =5.01.  Meunier  obtained  the  mineral 
artificially  by  treating  an  alloy  of  iron  and  chromium  at  a 
red  heat  with  hydrogen  sulphide. 

Smith  obtained  as  the  mean  of  three  analyses: 
S  42.69,  Cr  35.91,  Fe  20.10=98.70 

The  theoretical  composition  is: 
S  44.3,  Cr  36.3,  Fe  19.4  =  100 

The  chromium  content  of  iron  meteorites  soluble  in  nitric 
acid  or  aqua  regia  has  usually  been  ascribed  to  daubreelite 
but  as  Cohen  points  out*  this  is  only  allowable  when  suffi- 
cient sulphur  is  present  to  form  this  mineral. 

SCHREIBERSITE 

Phosphornickeleisen,  Rhabdite,  Dyslytite,  Lamprite, 
Glanzeisen,  Partschite 

The  name  schreibersite  was  first  applied  to  a  nickel-iron 
phosphide  occurring  in  the  form  of  large  crystals  or  grains. 
To  occurrences  of  the  same  substance  in  needle  or  plate-like 
forms  the  name  rhabdite  was  long  applied  as  it  was  at  first 
thought  to  be  a  different  mineral  from  schreibersite.  The 
composition  and  physical  properties  of  rhabdite  were, 
however,  shown  by  Cohen  to  be  the  same  as  those  of  schrei- 
bersite and  rhabdite  is  now  regarded  as  a  variety  of  schreiber- 
site. The  term  nickel-iron  phosphide  is  sometimes  used  as 
a  general  one  to  include  both  schreibersite  and  rhabdite,  but 
in  these  pages  the  term  schreibersite  is  used  as  a  general 
name  for  the  species. 

The  color  of  schreibersite  on  fresh  fracture  is  tin-white; 

*Meteoritenkunde,  Heft  II,  256. 


148  METEORITES 

it  tarnishes,  however,  readily  to  bronze-yellow.  When 
fresh  its  lighter  color  distinguishes  it  readily  from  pyrrhotite, 
kamacite  and  plessite  but  not  so  readily  from  taenite  and 
cohenite.  In  fact  it  has  often  probably  been  confounded 
with  taenite  but  though  resembling  that  alloy  in  color  it  can 
readily  be  distinguished  from  it  by  its  lack  of  elasticity. 
Schreibersite  is  extremely  brittle.  Its  hardness  is  about 
6.5.  Determinations  of  its  specific  gravity  vary  from  6.3 
to  7.3,  but  the  majority  of  determinations  give  a  value  near 
7.  Schreibersite  is  strongly  magnetic  and  may  be  made  to 
acquire  and  hold  polarity.  It  occurs  in  the  form  of  crystals, 
grains,  foliae,  and  especially  as  needles,  to  which  latter  form 
the  name  rhabdite  (pa/35o5,  a  rod)  is  applied. 

The  habit  of  the  crystals  varies  from  compressed-prismatic 
to  vertical-tabular.  The  crystals  sometimes  reach  a  length 
of  5X  inches  (14  cm.)  as  in  Carlton.  Owing  to  the  round- 
ing of  planes  and  angles  crystallographic  determinations 
have  not  thus  far  been  possible.  Often  a  hollowing  of  the 
ends  of  the  crystals  such  as  is  characteristic  of  pyromorphite 
occurs  and  in  one  such  hollow  on  a  crystal  from  Toluca, 
taenite  was  found.  Cleavage  in  three  perpendicular  direc- 
tions is  usually  observable,  that  perpendicular  to  the  length 
of  the  crystal  being  the  best  defined.  The  tetragonal  sys- 
tem of  crystallization  is  thus  indicated.  By  allowing  a 
crystal  of  Schreibersite  to  fall  on  paper,  separation  into 
cuboidal  forms  often  takes  place.  Disintegration  also  often 
occurs  by  mere  standing,  thus  suggesting  that  a  condition  of 
tension  like  that  shown  by  Prince  Rupert  drops,  exists. 
In  the  form  of  grains  or  flakes  Schreibersite  may  be  dis- 
cerned in  an  etched  section  or  its  presence  may  only  become 
known  upon  dissolving  the  nickel-iron.  In  Ilimae  isolated 
grains  were  observed  by  Tschermak  to  be  collected  in  the 
neighborhood  of  Reichenbach  lamellae.  Often  Schreibersite 
is  intergrown  with  pyrrhotite  and  graphite.  Graphite  no- 
dules may  serve  as  a  nucleus  for  the  growth  of  Schreibersite 
crystals  or  they  may  be  surrounded  by  an  envelope  of  the 
latter  mineral.  The  needle-like  or  lath-shaped  forms  of 
Schreibersite  known  as  rhabdite  usually  have  angular  termi- 
nations. They  are  usually  very  thin  in  proportion  to  their 


COMPOSITION   OF   METEORITES  149 

length.  In  thickness  Cohen  obtained  measurements  vary- 
ing from  .001  to  .05  mm.  while  in  length  some  were  5  mm. 
long.  In  the  latter  direction,  however,  the  measurement 
might  well  be  incomplete  since  the  needles  break  easily. 
The  width  of  the  5  mm.  crystal  was  1.5  mm.  Angular 
measurements  made  by  Deecke  and  Scheerer  showed 
values  close  to  90°.  Thus  the  tetragonal  form  is  further 
indicated.  Vertical  striations  often  characterize  the 
needles. 

In  the  irons  of  Santa  Rosa,  Seelasgen,  Braunau,  and 
Misteca  the  arrangement  of  rhabdite  was  found  to  be 
parallel  to  cubic  faces.  In  Indian  Valley,  Kunz  and  Wein- 
schenk  noted  an  arrangement  parallel  to  the  Neumann  lines. 
In  Hex  River  the  rhabdite  is  arranged  in  parallel  zones,  but 
the  needles  are  differently  oriented  in  each.  Zones  poor 
in  rhabdite  or  free  from  it  lie  between  those  rich  in  rhabdite. 
There  is  also  a.  difference  in  the  size  of  the  needles  in  the 
different  zones,  and  the  smaller  needles  appear  more  numer- 
ous and  more  crowded  than  the  larger.  A  similar  arrange- 
ment was  observed  by  Brezina  in  the  iron  of  Holland's 
Store.  In  Braunau,  according  to  Tschermak,  there  are 
gradations  from  true  rhabdite  needles  to  schreibersite-like 
foliae,  the  latter  being  bounded  by  three  planes  perpendicular 
to  each  other  and  arranged  partly  parallel  to  the  faces  of  the 
main  individual  and  partly  parallel  to  the  twinning  lamellae. 
This  is  explained  by  Tschermak  as  a  simultaneous  crystal- 
lization of  nickel-iron  and  schreibersite,  the  slow-forming 
twinning  lamellae  giving  the  schreibersite  more  opportu- 
nity to  extend  in  the  direction  of  breadth.  Somewhat 
similar  foliae  were  isolated  by  Cohen  from  Hex  River. 
The  largest  of  these  was  2.6  mm.  long,  1.6  mm.  broad,  but 
most  were  much  smaller.  Still  there  was  complete  separa- 
tion in  form  and  dimensions  between  needles  and  plates. 
The  plates  were  usually  bounded  by  six  planes  at  right 
angles  to  each  other,  the  four  subordinate  ones  being  prob- 
ably cleavage  planes.  On  some  of  the  edges  of  the  planes 
angles  of  about  150°  could  be  noted.  The  surface  of  the 
planes  was  either  smooth  or  corrugated,  the  corrugations 
running  sometimes  in  two  directions. 


150 


METEORITES 


Brezina*  noted  an  arrangement  of  schreibersite  lamellae 
parallel  to  the  planes  of  the  dodecahedron.  These  he  found 
in  Tazewell,  Ballinoo,  and  Narraburra.  The  plates  have 
the  same  relation  to  schreibersite  that  those  of  pyrrhotite 
(Reichenbach  lamellae)  have  to  that  mineral  except  that  the 
pyrrhotite  lamellae  are  arranged  parallel  to  the  cube,  while 
those  of  schreibersite  are  parallel  to  the  dodecahedron. 


FIG.  50. —  Brezina's  lamellae  (dodecahedral  schreibersite  lamellae)  as  seen  in  the 
Narraburra  meteorite. 

Cohen  has  given  the  name  of  Brezina's  lamellae  to  schrei- 
bersite plates  arranged  in  this  way.  The  accompanying 
figure  (Fig.  50)  shows  the  Brezina  lamellae  in  Narraburra 
as  observed  by  Liversidge.f 

Numerous  analyses  of  schreibersite  and  rhabdite  have 
been  made  all  indicating  a  formula  (Fe,  Ni,  Co)3P.  The 
ratio  of  Fe  :  Ni+Co  varies,  but  considered  as  3  :  I  which 
seems  to  be  about  the  average,  the  percentages  become  Fe 
62.6,  Ni+Co  21.9,  P  15.5.  In  view  of  the  large,  constant 
percentage  of  nickel,  Borgstrom  has  urgedf  that  the  formula 

*Sitzb.  Wien.  Akad.,  1904,  113,  1-7. 

tjour.  Roy.  Soc.  N.  S.  W.,  1903,  xxxvii,  PI.  xvii. 

JDie  Met.  v.  Hvittis  u.  Marj.,  Helsingfors,  1903,  67. 


COMPOSITION   OF   METEORITES  151 

of  schreibersite  should  be  regarded  as  Fe2Ni  P,  in  which  case 
the  percentages  would  be  Fe  55.5,  Ni  29.1,  P  15.4.  The 
percentage  of  Ni+Co  is  much  less  variable  apparently  in 
rhabdite  than  in  schreibersite.  A  complete  list  of  analyses 
follows.  In  cold,  dilute  acids  and  in  copper  ammonium 
chloride  schreibersite  is  insoluble,  the  latter  property  fur- 
nishing a  means  of  distinguishing  it  from  cohenite  and 
taenite.  Unlike  these  minerals  also  it  does  not  reduce  cop- 
per from  copper  sulphate  solution.  By  warm,  concentrated 
HC1  or  aqua  regia  schreibersite  is  easily  dissolved  and  thin 
plates  are  attacked  by  cold,  dilute  HC1. 

For  isolation  of  schreibersite  Meunier  recommends  boil- 
ing a  powder  of  the  mineral  with  a  concentrated  solution  of 
copper  sulphate,  separation  of  precipitated  copper  with 
fuming  nitric  acid,  treatment  of  the  residue  with  a  magnet 
to  separate  it  from  graphite,  and  solution  of  any  pyrrhotite 
present  by  treatment  with  dilute  nitric  acid.  Before  the 
blowpipe  schreibersite  fuses  easily  to  a  magnetic  globule. 
After  boiling  with  nitric  acid,  ammonium  molybdate  gives  a 
yellow  precipitate  of  ammonio-phospho-molybdate.  Heat- 
ing of  the  fine  powder  with  magnesium  wire  in  a  closed  tube 
and  treatment  of  the  assay  with  water  gives  hydrogen 
phosphide,  H3P,  recognizable  by  its  garlic-like  odor. 

Schreibersite  is  almost  universally  present  in  the  iron 
meteorites,  in  fact  is  perhaps  never  lacking  from  them. 
The  distribution  of  schreibersite  in  an  individual  meteorite 
is  usually  quite  irregular.  Thus  from  three  different  pieces 
of  Glorieta  Mountain  Cohen  obtained  values  varying  from 
2.85  to  8. 1 1  per  cent  of  schreibersite  according  to  what  part 
the  sample  was  taken  from,  and  similar  determinations  of 
Toluca  by  different  authorities  show  percentages  varying 
from  0.34  to  4.93  per  cent.  It  is  quite  impracticable, 
therefore,  to  determine  accurately  the  amount  of  schreiber- 
site in  a  meteorite  by  calculation  from  the  amount  of  phos- 
phorus obtained  in  a  single  analysis. 

As  between  schreibersite  and  rhabdite  the  octahedrites 
usually  contain  more  schreibersite,  the  hexahedrites  and 
ataxites  more  rhabdite.  Yet  both  may  occur  in  about 
equal  quantity  as  in  Seelasgen,  while  in  Magura  and  Sarepta 


152  METEORITES 

certain  parts  contain  an  excess  of  schreibersite  and  others 
of  rhabdite.  The  iron-stone  meteorites  usually  contain 
schreibersite,  as  do  probably  also  the  stone  meteorites.  At 
least  it  is  customary  to  assign  to  this  mineral  percentages 
of  phosphorus  shown  by  analyses.  Yet  this  amount  is 
sometimes  so  large,  e.g.,  0.76-0.91  per  cent  in  the  nickel- 
irons  of  Nerft,  Honolulu,  Zsadany  and  Bachmut  and  2.03 
per  cent  in  the  nickel-iron  of  Carcote  that  it  is  suggested  by 
Cohen*  that  it  is  questionable  whether  this  is  properly 
referable  to  schreibersite.  In  a  later  note  in  view  of  the 
discovery  of  free  phosphorus  in  Saline  by  Farrington, 
Cohen  suggests  that  the  phosphorus  may  be  present  in  the 
free  state. 

As  was  early  pointed  out  by  Smith,  schreibersite  is  a  min- 
eral peculiar  to  meteorites  and  one  of  the  most  significant 
in  interpreting  their  origin.  Terrestrially  phosphides  do 
not  occur,  since  free  oxygen  changes  them  to  phosphates. 
The  existence  of  schreibersite  in  meteorites  is  therefore, 
proof  of  absence  of  free  oxygen  where  they  were  formed. 
Tornebohm  has  reported  schreibersite  to  be  present  in  the 
terrestrial  iron  of  Ovifak,  his  determinations  being  based  on 
the  presence  of  magnetic  particles  with  metallic  luster  which 
did  not  precipitate  copper  from  a  copper  sulphate  solution 
and  were  only  slightly  attacked  by  hydrochloric  acid. 
Such  a  determination  is,  however,  too  incomplete  to  be 
reliable.  In  the  Santa  Catarina  iron  Daubree  found  a 
prismatic  crystal  terminating  in  eight  planes  which  he 
regarded  as  schreibersite.  Also  a  substance  isolated  by 
Derby  from  this  iron  by  means  of  dilute  hydrochloric  acid 
gave  percentages  on  analysis  by  Cohen  closely  approximat- 
ing the  composition  of  schreibersite.  A  number  of  iron 
or  nickel  phosphides  resembling  schreibersite  have  been 
obtained  artificially.  Thus  Sidot  by  allowing  vapor  of 
phosphorus  to  pass  over  piano  wire  in  a  porcelain  tube  at  a 
red  heat  and  later  heating  the  product,  obtained  in  the 
interior  of  the  metallic  mass  hard,  steel-colored,  four-sided 
prisms,  reaching  a  centimeter  in  size  and  having  the  com- 
position Fe4P  (P  1 2. i  per  cent).  By  fusion  of  calcium 

*Meteoritenkunde,  Heft  I,  136. 


COMPOSITION   OF   METEORITES  153 

phosphide,  powdered  charcoal,  and  nickel  oxide,  Gamier 
obtained  a  compound  having  the  formula  Ni5P.  It  was  in 
the  form  of  long,  prismatic,  light  yellow  crystals  determined 
by  Jannetaz  to  be  tetragonal.  Their  hardness  was  5.5; 
sp.  gr.  7.283. 

By  slight  heating  of  finely  divided  iron  in  vapor  of  phos- 
phorus Hvoslef  obtained  a  compound  having  the  formula 
Fe2P  from  which  by  strong  heating  under  a  cover  of  borax, 
a  regulus  of  dark  iron-gray  color,  brittle,  magnetic,  and  at- 
tacked neither  by  hydrochloric  or  nitric  acids  resulted.  It 
contained  16  per  cent  P,  corresponding  to  the  formula 
Fe3P.  G.  =  6.28. 

Rhabdite-like,  steel-gray,  brittle,  magnetic,  tetragonal 
prisms  were  found  by  Mallard  accompanying  augite  and 
anorthite  among  the  products  of  a  furnace  at  Commentry. 
After  subtracting  Fe  and  As  the  composition  of  the  substance 
corresponded  to  the  formula  Fe7P2. 

ANALYSES  OF  SCHREIBERSITE 

P  Fe          Ni  Co         Cu          Total     Substance  Fe+Ni+Co:P 

taken 

1  16.10    72.62     10.72      0.56       loo  0.5375         2.869:1 

2  16.04    69.55          H-41  loo  2.877 

3a       15.74    69.54     13-81       1.31       100.40        0.4499         2.955 

3b       15.80    70.07     14.57      0.43       0.03         100.90        0.8030         2.959 

4  15.70  61.78  21.93  0.38  0.21  loo  0.6886  2.937 

5  15.70  54.12  29.71  0.47       loo  0.5045  2.925 

6  15.68  50.52  33.90  0.62  0.22  100.94  0.6761  2.955 

7  15.49  63.36  19.63  1.23  ....  99.71  0.4086  2.978 

8  15.47  65.75  i8.35  0.43  ....  loo.oo  0.5644  2.996 

9  15.45  54.43  29.36  0.67  0.34  100.25  0.3260  2.990 

10  15.45  7I-7°  12.58      0.32       100.05  0.6490  3.014 

11  15.37  58.54  26.08  0.05         tr.  100.04  3.009 

12  15.38  63.97  19.15       1.68       100.18  0.4115  3.020 

13  15-31  57-46  25.78  1.32       ....  99.87  0.1328  3.015 

14  15.01  57-11  28.35          tr 100.47  3.106 

15  15.00  64.69  20.11  99.80  3.099 

16  14.93  55.15  29.15       0.21  ....  99.44  0.5152  3.086 

17  14.88  66.92  18.16      0.62  ....  100.58  0.4023  3.158 

18  14.86  56.53  28.02      0.28  99.69  3.113 

....    100.00   0.619    3  •  J72 

0-13    98.97  3  •  171 

....    100.00  3  .  277  : 

loo.oo  0.028  3  . 324  ; 

99-94  3-419: 

13.51     56.12          29.18  98.81  3.443: 


154  METEORITES 

REFERENCES 

1.  Zacatecas.     Scherer:   Meteoritenkunde,  Heft  I,  131.      Calculated  to  100, 
after  deduction  of  4.60  per  cent  chromite  and  0.88  per  cent  daubreelite. 

2.  Cranbourne.     Flight:   Ph.  Tr.,  1882,  892;  mean  of  two  analyses.     Nickel 
determined    by  difference.     "Large,   brass-yellow   prisms,   with   distinctly   basal 
cleavage,  slowly  soluble  in  muriatic  or  nitric  acid." 

33.  S.  Juliao  de  Moreira.  Cohen:  N.  J.,  1889,  i,  220;  mean  of  two  analyses; 
brittle,  steel-gray,  crystalline  fragments,  shading  to  bronze-yellow. 

3b.  S.  Juliao  de  Moreira.  Fahrenhorst:  Meteoreisenstudien,  xi,  A.  N.  H. 
Wien,  1900,  xv,  389.  The  determination  of  Cu  was  made  on  19.183  grams. 

4.  Kendall  County.     Scherer:   Meteoritenkunde,  Heft  II,  233. 

5.  Mount  Joy.     Fahrenhorst:    Meteoreisenstudien,  xi,  A.  N.  H.  Wien,  1900, 
xv,  388.     Slight  mixture  of  rhabdite.     Calculated  to  100  after  deduction  of  0.42 
per  cent  chromite  and  silicate. 

6.  Magura.      Fahrenhorst:    Meteoreisenstudien,  xi,    A.   N.    H.  Wien,    1900, 
xv,  3  77. 

7.  Glorieta  Mountain.     Cohen  and  Weinschenk,  A.  N.  H.  Wien.,  1891,  157; 
large  and  very  brittle  crystals. 

8.  Bischtiibe.     Cohen:    Meteoritenkunde,   Heft  I,  131.      Calculated   to  100, 
after  deduction  of  0.07  per  cent  residue. 

9.  Cosby     Creek.     Fahrenhorst:  Meteoreisenstudien,  xi,  A.  N.  H.  Wien,  1900, 
xv,  372. 

10.  De  Sotoville.     Cohen:    Meteoritenkunde,  Heft  II,  233. 

11.  Canyon  Diablo.     Tassin:    Smithsonian  Misc.  Coll.,  1908,  50,  212.     Flat- 
tened and  angular  nodules  and  rounded  grains.     0-7.20. 

12.  Toluca.     Cohen  and  Weinschenk:   A.  N.  H.  Wien,  1891,  vi,  138;    very 
brittle  crystals,  up  to  5  mm.  in  length,  tin-white  and  very  lustrous;  cobalt  prob- 
ably estimated  too  high  on  the  basis  of  the  nickel;  no  copper. 

13.  Hraschina.     Cohen    and    Weinschenk:     A.  N.  H.  Wien,    1891,    vi,    149. 
Fragments. 

14.  Toluca.     Meunier:  A.  Ch.  P.  (Paris),  1869  (4),  xvii,  45,  57;  microscopic 
scales,  slowly  soluble  in  warm  muriatic  acid;  trace  of  magnesia. 

15.  Casas  Grandes.     Tassin:    Proc.  U.  S.  Nat.  Mus.,  1902,  xxv,  73. 

16.  Marjalahti.     Borgstrom:    Die  Meteoriten  von  Hvittis  und    Marjalahti, 
1903,  66. 

17.  Beaconsfield.      Sjostrom:      Monatsberichte     Berlin    Akad.,     1897,    1040. 
Large  crystals. 

18.  Tazewell.     Smith:   Am.  Jour.  Sci.,   1885   (2),  xix,  157;  yellow,  irregular 
spangles. 

19.  Bohumilitz.     Berzelius:    Pogg.  Ann.,  xxvii,   131;  gilt  scales;   calculated 
to  100,  after  deduction  of  2.04  Si.  and  1.42  C. 

20.  Canyon  Diablo.     Florence:   Am.  Jour.  Sci  ,  1895   (3),  49,  107.     From  a 
vein  enclosed  by  cohenite      Tin  found  qualitatively. 

21.  Cambria.     Silliman  and  Hunt:   Am.  Jour.  Sci,  1846  (2),  ii,  375;  blackish- 
gray  folia,  mixed  with  bright  flakes;  calculated  to  IOO  after  deduction  of  10  per  cent 
Si.     The  analysis  gave  a  sum  of  only  90  per  cent. 

22.  Elbogen.     Berzelius:   Pogg.  Ann.,  1834,  xxxiii,  137. 

23.  Canyon  Diablo.     Tassin:  Smithsonian  Misc.  Coll.,  1908,50,211.     Broad, 
thin,    dark  steel-gray,  flexible,  magnetic  lamellae.     0  =  7.09. 

24.  Cranbourne.     Flight:    Ph.  Tr.,   1882,  892;  very  brittle,  coarse  powder, 
readily  soluble  in  concentrated  muriatic  acid. 


COMPOSITION   OF   METEORITES  155 

ANALYSES  OF  RHABDITE 

P  Fe  Ni  Co          Cu         Total      Amount  Fe+Ni-f- 

taken  Co  :  P 

1  16.35       48-8S       33   !5       :  65       ••••       100.00       2.780: 

2  iS-49       5i-io      32.99      0.42       100.00      0.2563  2.967: 

3  15.46       56.71       27.36      0.47       ....       100.00      0.2772  2.984: 

4  IS-32      55-3°      28.78      0.60       ....       100.00      0.3276  3.015: 

5  15.09  52.42              33.51  0.25  101.27  0.476  3.106: 

6  15-05  41.54  42.61      0.80  ....  100.00  0.0986  3.053: 

7  15.03  52.54  31.71      0.72  ....  100.00  0.5985  3.076: 

8  14.86  46.22  37.98      0.96  ....  loo.oo  0.2255  3-107:1 

9  12.95       49-33  38.24  100.52  ....      3-672:1 

REFERENCES 

1.  Santa  Rosa.     Coahuila:   Wichelhaus,  Pogg.  Ann.,  1863,  cxviii,  633;  glisten- 
ing needles  insoluble  in  nitric  acid. 

2.  Lime  Creek.     Cohen:   A.  N.  H.  Wien,  1894,  ix,  115.   Calculated  to   100, 
after  deduction  of  1.54  per  cent  chromite  and  2.62  per  cent  daubreelite;  the  analy- 
sis gave  only  95.57  per  cent. 

3.  Hex  River  Mountains.     Cohen:    A.  N.  H.  Wien,    1894,  ix,  no.     Calcu- 
lated to  100  after  deduction  of  0.53  per  cent  chromite  and  0.68  per  cent  daubree- 
lite. 

4.  Sancha  Estate,  Coahuila.     Cohen:  A.  N.  H.  Wien,  1894,  ix,  106.     Calcu- 
lated to  100,  after  deduction  of  0.43  per  cent  chromite  and  0.28  per  cent  carbon. 

5.  Bendego.     Florence:  Ann.  Mus.  Nac.,  Rio  de  Janeiro,  1896,  ix,  182.  Mixed 
with  schreibersite.     Trace  of  tin.     Material  not  treated  with  salt  of  copper. 

6.  Beaconsfield.     Sjostrom:     Monatsber.    Berlin    Akad.,    1897,    1041.     Iron 
determined  by  difference.     Cobalt  determination  incomplete. 

7.  Bolson  de  Mapimi.     Cohen:  A.  N.  H.  Wien,  1894,  ix,  103.     Calculated  to 
IOO,  after  deduction  of  0.96  per  cent  residue  and  2.15  per  cent  daubreelite. 

8.  Seelasgen.     Cohen:   Meteoreisenstudien,  V,  A.  N.  H.  Wien,  1897,  xii,  52. 

9.  Cranbourne.      Flight:    Ph.  Tr.,    1882,  891.      Apparently  quadratic,  very 
brittle  prisms,  impervious  to  muriatic  acid.     Identified  by  Flight  with  rhabdite. 

COHENITE 

Lamprite  in  part 

Cohenite  is  a  carbide  of  iron,  nickel  and  cobalt,  having  the 
formula  (Fe,  Ni,  Co)3C.  It  is  found  chiefly  in  the  iron 
meteorites  of  the  group  of  coarse  octahedrites,  having  been 
identified  in  Beaconsfield,  Bendego,  Canyon  Diablo,  Magura, 
and  Wichita  County.  It  appears  as  silver-white,  strongly 
magnetic  and  brittle  crystals  oxidizing  to  bronze  yellow  or 
tomback  brown.  Streak  gray-black.  Hardness  5.5-6.  Sp. 
gr.  7.20-7.65,  (Hussak  6.18).  Cohenite  is  insoluble  in  dilute 
HC1  but  is  slowly  dissolved  by  concentrated  acid,  and  gives 
off  in  the  latter  process  a  petroleum-like  odor.  It  is  also 
soluble  in  copper  ammonium  chloride. 


156  METEORITES 

It  was  first  distinguished  as  a  separate  mineral  by  Wein- 
schenk  in  1889,  having  been  previously  mistaken  for  schreib- 
ersite.  It  differs  from  schreibersite  in  being  infusible  and 
in  giving  no  precipitate  with  ammonium  molybdate. 
Crystals  of  cohenite  are  usually  of  elongated  form  and  are 
often  arranged  parallel  to  the  octahedral  bands  of  their 
host.  Definite  forms  have  been  described  only  by  Hussak* 
who  found  them  constituting  crystalline  aggregates  in  the 
Bendego  meteorite.  By  dissolving  the  iron  in  weak  acid 
these  aggregates  became  separated  and  on  the  crystals  so 
obtained  Hussak  identified  the  following  isometric  forms: 
0(100),  o(in),  d(no),  p(22i)  and  probably  (311),  (322) 
and  (944).  The  habit  of  the  crystals  was  tabular.  In  Ma- 
gura  they  reach  a  length  of  8  mm.  Carbides  of  composition 
similar  or  nearly  similar  to  cohenite  are  found  in  artificial 
iron  and  in  the  native  iron  of  Greenland. 

ANALYSES  OF  COHENITE 
Fe  Ni  Co  C  Total    Fe+Ni+Co  :  C 

1  94.34  0.13  5.53  100  3.67 

2  9I-69  2.21  6.10  100  3-30 

3  91.45  2.47  o.io  5.98  ioo  3.35 

4  91.31  1.77  0.25  6.67  ioo  3.00 

5  91.06  2.20  6.73  IOO  2.97 

6  90 .94  2.22  0.30  6.54  IOO  3  .  06 

7  90.80  2.37  0.16  6.67  ioo  3.00 

8  89.81  3.08  0.69  6.42  ioo  3  .  ii 

REFERENCES 

1-2.  Canyon  Diablo.  Florence:  Am.  Jour.  Sci.,  1895  (3),  xlix,  105-106. 
I.  Isolated  crystals  after  deducting  3.64  per  cent  schreibersite.  2.  Plates  inter- 
grown  with  schreibersite. 

3.  Canyon  Diablo.    Tassin:  Smithsonian  Misc.  Coll.,  1907,  50,  212.   Thin  plates 
and  rounded  grains.     Calculated  to  ioo  after  deducting  .18  per  cent  schreibersite. 

4.  Canyon  Diablo.     Fahrenhorst:  A.  N.  H.  Wien,  1901,  xvi,  375.     Calculated 
to  ioo  after  deducting  4.68  per  cent  of  schreibersite. 

5.  Bendego.     Dafert:  Meteoritenkunde,  Heft  I,  117.     Calculated  to  ioo  after 
deducting  5.68  per  cent  schreibersite. 

6.  Beaconsfield.     Sjostrom:  Monatsber.  Berlin  Akad.,  1897, 1043.     Calculated 
to  ioo  after  deducting  26.12  per  cent  schreibersite. 

7.  Wichita.     Sjostrom:  Zeitschriftfiir  anorgan.  Chemie,  Hamburg  and  Leipzig, 
1896,  xiii,  57.     Calculated  to  ioo  after  deducting  9.35  per  cent  schreibersite. 

8.  Magura.     Weinschenk:    A.  N.  H.  Wien,  1889,  iv,  95.    Mean  of  three  anal- 
yses   calculated    to  ioo  after  deducting  .65    per  cent  schreibersite.     Traces  of 
Cu-and  Sn  found. 

*Arch.  Mus.  Nac.  Rio  de  Janerio,  1896,  9,  161-5. 


COMPOSITION   OF   METEORITES  157 

MOISSANITE 

A  silicide  of  carbon  having  the  formula  SiC  was  first 
found  by  Moissan*  in  the  residue  left  after  dissolving  a 
53  kg.  piece  of  Canyon  Diablo  in  hydrochloric  acid,  and 
treating  this  residue  with  hydrofluoric  acid  and  boiling 
sulphuric  acid.  The  mineral  occurred  in  the  form  of  small 
hexagonal  crystals  of  a  generally  green  color  but  varying 
from  pale  green  to  emerald  green.  Specific  gravity  3.2. 
The  mineral  was  unattacked  by  acids  but  gave  potassium 
silicate  on  fusion  with  caustic  potash  and  CO2  on  fusion 
with  lead  chromate.  Kunzf  suggested  the  name  moissanite 
for  the  mineral  in  honor  of  its  discoverer.  In  physical  and 
chemical  properties  the  mineral  agrees  with  the  previously 
known  and  artificially  produced  carborundum.  Forty-four 
crystal  forms  have  been  identified  on  carborundum  but  none 
on  moissanite.  Moissan  simply  stated  that  the  edges  of 
the  crystals  observed  by  him  were  well-formed  and  the  sides 
perpendicular. 

LAWRENCITE 

This  name  is  applied  to  ferrous  chloride,  FeCl2,  found 
sometimes  in  solid  form  but  usually  deliquescent  in  green 
drops  on  meteorites.  The  solid  form  has  been  reported  only 
in  the  meteorites  of  Laurens,  Smith  Mountain,  and  Taze- 
well.  These  are  all  fine  octahedrites  with  high  percentages 
of  nickel.  Little  description  of  the  appearance  of  the  sub- 
stance was  given  by  the  finders.  It  was  simply  stated  that 
it  occurred  in  crevices  and  became  soft  on  exposure.  The 
name  lawrencite  was  given  to  the  mineral  by  Daubree  in 
honor  of  J.  Lawrence  Smith. J  More  frequent  than  the 
solid  form  of  the  mineral  is  the  occurrence  in  the  manner 
first  described  by  Jackson  in  the  meteorite  of  Limestone 
Creek. §  Jackson  states  that  having  washed  the  iron  several 
times  in  distilled  water  he  filed  one  side  of  it  bright  and  left 
it  exposed  to  the  air.  In  a  few  days  numerous  drops  of  a 

*Comptes  Rendus,  1904,  139,  778,  and  1905,  140,  405-406. 

fAm.  Jour.  Sci.,  1905,  19,  396-397. 

JC.  R.,  1877,  84,  69. 

§Am.  Jour.  Sci.,  1838,  i,  34,  333. 


158  METEORITES 

grass-green  liquid  collected  on  the  surface  of  the  iron  and 
these  soon  became  externally  coated  with  a  thin,  brown 
film.  The  drops  had  a  slightly  alkaline,  astringent  taste  but 
gave  no  alkaline  reaction  with  turmeric  paper.  Qualitative 
tests  showed  the  presence  of  iron,  nickel,  and  chlorine. 
Quantitative  analysis  (reduced  to  percentages  by  Cohen*) 
gave: 

Fe  Ni  Cl 

51.02  18.14  30.84  =  100 

Fe+Ni  :  Cl  =  i.4  :  i  ~ 

Analysis  of  scraped  material  was  also  made  by  Jackson 
and  another  by  Hayes  but  these  analyses  appear  to  have 
been  much  contaminated  by  foreign  material.  All  show 
higher  percentages  of  iron  than  normal  ferrous  chloride  and 
thus  indicate  that  impure  material  was  used.  The  per- 
centages for  pure  ferrous  chloride  are: 

Fe  Cl 

44-i  55-9 

On  exposure  to  the  air,  lawrencite  rapidly  turns  brown 
and  becomes  earthy,  showing  a  change  to  ferric  chloride 
(molysite),  and  ferric  hydroxide  (limonite).   The  reaction  is: 
6FeCl2+3O+3  H2O  =  Fe2  O6H6+4Fe  Cl, 

The  ferric  chloride  is,  however,  reduced  by  contact  with 
iron  to  form  ferrous  chloride  again : 

4FeCl3+2Fe=6FeCl2 

so  that  the  process  is  continuous.  In  addition  there  may 
occur  a  formation  of  free  acid  through  hydrolysis  of  ferric 
chloride: 

4  Fe  Cl3+6  H2O  =  Fe2O6H6+6  HC1+2  Fe  Cl, 

In  connection  with  these  chemical  changes  there  is  an 
increase  of  volume  which  causes  splitting  and  disintegration 
of  the  meteorite. 

All  lawrencite  of  meteorites  shows  qualitatively  and 
quantitatively  nickel  present  with  the  iron.  This  probably 
gives  the  green  color  to  the  mineral  as  compared  with 

*Meteoritenkunde,  1894,  Heft  I,  231. 


COMPOSITION   OF  METEORITES  159 

ferrous  chloride  which  is  colorless.  The  latter  has  been 
reported  at  Vesuvius.  Meteoritic  lawrencite  is,  then,  a 
mixture  of  iron  and  nickel  chlorides.  It  was  early  suggested 
that  the  lawrencite  of  meteorites  was  not  a  primary  con- 
stituent, and  might  have  been  formed  by  the  absorption  of 
chlorine  by  the  meteoric  mass  from  the  earth's  atmosphere 
or  the  soil.  This  was  the  view  of  Shepard*  and  Mallet. | 
But  as  lawrencite  varies  in  quantity  in  meteorites  and  ex- 
udes from  pieces  freshly  cut  from  the  interior  of  meteor- 
ites, there  can  be  little  doubt  that  it  is  an  original  con- 
stituent. It  is  known  to  be  present,  as  has  been  mentioned, 
in  clefts  and  hollows  and  it  is  also  regarded  by  Cohen  as 
distributed  "in  the  intermolecular  spaces. "J  Its  dis- 
tribution is  indicated  in  a  general  way  in  a  meteorite  by 
areas  inclined  to  rust.  The  borders  of  accessory  con- 
stituents are,  as  is  well  known,  especially  liable  to  such  a 
change.  Cohen  thinks  it  probable  that  the  lawrencite  of 
a  meteorite  gradually  works  outward  by  diffusion.  He 
bases  this  view  upon  the  fact  that  in  the  unaltered  interior 
of  Forsyth  he  found  0.17  per  cent  of  chlorine  but  in  the 
rust  crust  4.99  per  cent.  Nevertheless  it  is  highly  probable 
also  that  the  lawrencite  is  more  or  less  irregularly  distributed. 
In  Deep  Springs  the  non-rusted  portion  showed  0.016  per 
cent  chlorine,  and  the  easily  rusting  portion  0.99  per  cent, 
while  Venable  found  0.39  per  cent  in  a  mass  analysis.  In 
Deep  Springs,  as  in  the  Cape  iron  and  Lick  Creek,  the  easily 
rusting  portions  are  divided  by  rather  sharp  boundaries 
from  those  which  do  not  rust.  Probably  through  a  process 
of  diffusion  to  the  surface  and  thus  of  escape,  the  lawrencite 
of  a  meteorite  often  seems  to  disappear  after  a  time.  This 
exhaustion  is  shown  by  a  cessation  of  the  tendency  to  rust. 
Cohen  describes  such  a  cessation  in  a  section  of  the  Cape 
iron  after  a  period  of  15  years,  and  in  one  of  Sao  Juliao  after 
a  much  shorter  time. 

The  presence  of  chlorine,  indicating  lawrencite,  is  often 
reported  in  iron  meteorites  in   appreciable  percentages  by 

*Am.  Jour.  Sci.,  1842,  i,  43,  359-362. 
fAm.  Jour.  Sci.,  1871,  3,  2,  14. 
|Meteoritenkunde,  1903,  Heft  II,  266. 


160  METEORITES 

analysts,  the  largest  per  cent  found  being  1.48  per  cent, 
reported  by  Jackson  in  Limestone  Creek.  According  to 
experiments  made  by  Cohen,*  the  extraction  of  chlorine 
for  analysis  can  best  be  made  by  digesting  a  few  grams  of 
the  meteorite  in  dilute  sulphuric  acid.  Dilute  nitric  acid 
or  boiling  water  is  less  effectual  for  this  purpose.  It  is  to 
the  presence  of  lawrencite  in  meteorites  that  their  fre- 
quently observed  "sweating"  is  doubtless  to  be  ascribed. 
Over  the  surface  of  such  meteorites  the  continuous  forma- 
tion of  liquid  drops  may  be  observed  and  relatively  rapid 
decomposition  of  the  mass  takes  place,  at  least  until  a 
protective  crust  is  formed.  Conspicuous  examples  of  such 
meteorites  are  Cranbourne  and  Toluca.  Other  meteorites, 
such  as  St.  Genevieve,  some  individuals  of  Canyon  Diablo, 
etc.,  show  no  tendency  to  sweating  or  rusting  although  in  a 
fall  consisting  of  numerous  individuals,  such  as  Toluca  and 
Canyon  Diablo,  there  is  marked  difference  in  the  rusting 
tendency  of  different  individuals.  Lawrencite  seems  to  be 
almost  wholly  associated  with  nickel-iron  and  to  be  con- 
fined, therefore,  largely  to  the  iron  meteorites.  "Sweating" 
of  some  iron-stone  and  stone  meteorites  indicating  the  prob- 
able presence  of  lawrencite  in  them  has,  however,  been  ob- 
served. Such  meteorites  include  Crab  Orchard,  Hainholz, 
Morristown,  and  Sierra  deChaco  among  the  iron-stones  and 
Charwallas,  Marion,  and  Nagaya  among  the  stones. 

Other  salts  besides  lawrencite  soluble  in  water  have  been 
found  in  some  meteorites,  chiefly  carbonaceous  ones,  the 
porous  texture  of  which  suggests  absorption  or  formation  of 
these  salts  from  the  earth's  atmosphere  rather  than  their 
existence  as  primary  constituents.  The  soluble  salts  so 
found  include  chlorides  and  sulphates  of  sodium,  potassium, 
ammonium,  magnesium,  and  calcium.  They  are  usually 
found  in  the  water  extract  of  the  meteorite  but  occasionally 
are  obtained  as  sublimates  from  heating  the  meteorite  in 
powdered  form. 

WATER 

Water  is  as  a  rule  conspicuous  by  its  absence  from  mete- 
orites, yet  in  some  occurs  in  appreciable  quantities.  As 

*Meteoritenkunde,  1903,  Heft  II,  266 


COMPOSITION   OF   METEORITES  161 

the  meteorites  in  which  it  is  chiefly  found  are  of  a  porous 
nature,  some  authorities  are  inclined  to  regard  its  origin  in 
meteorites  as  always  terrestrial.  It  is  perhaps  never  a 
primary  constituent  and  yet  some  meteorites  which  have 
been  picked  up  immediately  after  their  fall  show  a  rusting 
of  the  interior  which  would  seem  pre-terrestrial.  In  the  car- 
bonaceous meteorites  Alais,  Cold  Bokkeveld,  Nagaya,  and 
Orgueil,  water  has  been  found  in  quantities  of  from  6  to  II 
per  cent.  From  these  it  is  obtained  by  heating  to  a  tem- 
perature above  100°  C.  In  other  stony  meteorites  such  as 
Bishopville,L'Aigle,  and  Pultusk,  water  has  been  obtained  in 
quantities  of  from  o.i  to  1.43  percent  by  heating  the  stone 
to  redness.  Part  of  such  water  doubtless  exists  in  com- 
bination, as  for  example,  with  iron  forming  iron  hydroxide 
and  it  has  been  suggested  that  part  may  be  formed  from 
hydrocarbons  by  heating.  No  mineral  in  meteorites  except 
limonite  (if  that  be  an  original  constituent)  possesses  water. 
Pisani  observed  that  the  powder  of  the  Orgueil  meteorite 
which  lost  9.15  per  cent  water  by  drying,  took  up  7  per  cent 
again  in  a  few  hours. 

QUARTZ 

On  the  whole,  quartz  is  conspicuous  by  its  absence  from 
meteorites.  It  has,  however,  been  identified  in  several 
irons,  though  almost  wholly  in  their  superficial  portions. 
This  has  caused  some  authorities  to  doubt  whether  quartz 
is  ever  an  original  constituent,  but  there  are  reasons  for 
believing  that  it  is  so. 

The  first  satisfactory  observation  of  quartz  in  meteorites 
was  by  Rose*  of  grains  which  he  observed  in  the  crust  of 
one  of  the  Toluca  irons.  These  were  further  studied  in  1895 
by  Laspeyresf  who  found  in  the  earthy,  loamy  crust  of  a 
Toluca  individual  weighing  10  kilos  numerous  brilliant 
quartz  crystals  reaching  a  _size  of  2  mm.  The  crystals 
showed  the  forms  oo  R  (1010),  R  (ion)  and  — R  (oili). 
They  also  Rad  the  usual  characters  of  siliceous  meteoritic 
minerals  in  being  fissured  and  brittle  and  in  showing  rounded 

*Monatsber.  Berlin  Akad.,  1861,  406-407. 
fZeitschrift  fur  Kryst.,  1894,  xxiv,  485-488. 


162  METEORITES 

edges  and  solid  angles.  The  specific  gravity  was  2.65. 
Index  of  refraction  about  that  of  Canada  balsam.  High 
interference  colors.  Silica  skeleton  with  salt  of  phosphorus. 
Soluble  in  hydrofluoric  acid.  Unaltered  by  strong  heating 
in  the  oxidizing  flame.  Other  occurrences  of  quartz  have 
been  noted  in  the  insoluble  residues  of  meteoric  irons.  Thus 
Joy  found  in  the  insoluble  residue  of  Cosby  Creek  some 
white,  opaque,  and  some  transparent  grains  which  would 
scratch  glass  but  not  quartz  and  which  he,  therefore,  re- 
garded as  quartz.  Similar  residues  were  found  by  Cohen 
and  Weinschenk  in  all  the  irons  they  investigated.  These 
included  Beaconsfield,  Bischtiibe,  Glorieta  Mountain,  Hex 
River  Mountains,  Ivanpah,  Kokstad,  Lime  Creek,  Locust, 
Magura,  Misteca,  Rasgata,  Schwetz,  and  Toluca.  The 
grains  found  were  colorless  and  transparent  and  averaged 
less  than  o.i  mm.  in  diameter.  From  the  pyrrhotite  of 
Caille  and  Charcas  apparent  quartz  grains  were  isolated 
by  Daubree  and  from  the  schreibersite  of  Sao  Juliao  by 
Cohen.  In  none  of  these  occurrences  has  the  quartz  been 
found  in  place,  hence  its  existence  as  a  fundamental  consti- 
tuent of  meteorites  is  not  altogether  certain,  but  indications 
point  strongly  to  a  pre-terrestrial  origin  for  the  grains  found. 

TRIDYMITE 

Asmanite 

Tridymite  has  been  identified  in  the  iron-stone  meteorite 
of  Steinbach  and  its  probable  presence  has  been  reported  in 
Vaca  Muerta'and  Crab  Orchard,  which  are  also  iron-stone 
meteorites,  and  in  the  stone  meteorite  Fisher.  In  Steinbach 
the  tridymite  occurs  as  colorless,  rounded  grains  or  plates 
which  reach  3  mm.  in  their  largest  dimension.  They  are 
generally  stained  with  iron  superficially  and  like  other 
meteoritic  minerals  are  much  rounded.  The  grains  also  are 
brittle  and  have  a  resinous  luster.  The  hardness  is  given 
as  5-5  by  Maskelyne,  6.5  by  Rath.  Specific  gravity  2.24- 
2.27.  Maskelyne  regarded  the  mineral  as  orthorhombic 
and  considered  it,  therefore,  a  new  species  to  which  he  gave 
the  name  asmanite  from  dsman,  the  Sanskrit  word  for 


COMPOSITION   OF   METEORITES  163 

thunderbolt.*  Assuming  an  orthorhombic  form  for  the 
mineral  Maskelyne  distinguished  twelve  forms,  the  equiva- 
lents of  which  in  the  now  generally  accepted  hexagonal 
system  have  not  as  yet  been  determined. 

The  existence  of  tridymite  in  a  meteorite  shows,  according 
to  the  researches  of  Wright  and  Larsen,t  that  it  has  been 
heated  to  a  temperature  above  800°  C,  since,  tridymite 
forms  between  800°  and  1625°  C. 

MAGNETITE 

Several  stone  or  iron-stone  meteorites  have  been  found  to 
contain  black,  magnetic  grains  which  dissolved  in  hydro- 
chloric acid  without  effervescence  to  form  a  yellow  solution. 

In  the  meteorites  of  Shergotty  and  Dona  Inez  these  are 
sufficiently  abundant  to  form  an  essential  constituent,  in 
Shergotty  constituting  4.57  per  cent.  Similar  grains  occur 
as  inclusions  in  maskelynite,  pyroxene,  and  chrysolite  in 
the  above  and  other  meteorites.  They  are  regarded  as 
magnetite. 

No  well-marked  crystals  of  meteoritic  magnetite  have  as 
yet  been  described. 

In  several  iron  meteorites  magnetite  has  been  reported 
as  a  constituent  but  few  analyses  have  been  made.  Tassinf 
observed  a  chromiferous  magnetite  occurring  as  rounded 
grains  of  blue-black  color  and  dull  luster  in  Canyon  Diablo, 
associated  with  "troilite  and  silicon  compounds  in  areas 
rich  in  carbon."  Analysis  gave: 

Fe2O3  65.25 
FeO  30.05 
Cr2O3  5 . 20 

100.50 

Meunier  analyzed  magnetite  from  the  crust  of  Toluca 
obtaining  the  material  by  first  treating  the  crust  with 

*Phil.  Trans.,  1871,  161,  361. 
fAm.  Jour.  Sci.,  1909,  4,  27,  423. 
JProc.  U.  S.  Nat.  Mus.,  1908,  34,  687. 


164  METEORITES 

chloride  of  mercury,  then  with  very  dilute  HC1  and  then 
with  magnets.     His  analysis  gave: 

Fe2O3  68.93 
FeO  28.12 
NiO  2 . oo 
CoO  tr. 

99.05' 

That  the  crust  formed  upon  the  surface  of  iron  meteorites 
in  passing  through  the  air  has  the  composition  of  magnetite 
was  also  shown  by  Farrington*  from  an  analysis  of  such  a 
crust  upon  the  Quinn  Canyon  meteorite  by  Nichols.  The 
analysis  calculated  to  100  after  deduction  of  extraneous 
compounds  gave: 

Fe2O3  72-38 
FeO  27.62 

100. 

CHROMITE 

Chromite  is  a  common  constituent  of  meteorites,  being 
not  infrequent  in  the  irons  and  almost  universally  present 
in  the  stones.  It  occurs  in  the  stones  usually  in  the  form  of 
grains,  often  of  microscopic  dimensions,  though  sometimes 
as  large  as  a  pea.  In  thin  sections  it  can  usually  be  readily 
recognized  by  its  translucent  ruby  to  purple  color  and  iso- 
tropic  characters.  In  the  irons  it  usually  occurs  in  nodules, 
sometimes  of  considerable  size,  as  in  the  case  of  one  of  the 
Coahuila  irons,  where  one  of  oval  form  found  by  Smith 
measured  5x7  inches  (12  x  17  mm.)  in  diameter.  This  was 
a  black,  granular  mass,  feebly  translucent  and  of  dark  red- 
dish-purple color.  In  other  irons,  as  in  Carthage,  Schwetz, 
and  Bendego,  chromite  occurs  closely  associated  with  pyr- 
rhotite  and  cohenite.  It  is  usually  in  octahedral  crystals 
averaging  about  one  millimeter  in  diameter.  From  Bendego 
highly  modified  crystals  were  obtained  by  Hussak,f  and  the 
following  forms  determined:  in,  no,  100,  553,  774,  221, 

*Pubs.  Field  Museum,  1910,  Geol.  Ser.,  iii,  176. 
fAnn.  Mus.  Nac.  Rio  de  Jan.,  1896,  9,  165-171. 


COMPOSITION   OF   METEORITES  165 

552,  331,  441,  211,  311,  210,  310,  510.  Only  a  few  of  these 
forms  occur  in  terrestrial  chromites.  The  octahedron  pre- 
dominated, but  the  crystals  were  often  tabular  from  the 
large  development  of  two  of  the  planes.  In  Ensisheim 
Shepard  identified  the  forms  in  and  no;  in  Lodran  Lang 
observed  in,  no,  and  311;  and  in  Greenbrier  County 
Fletcher  reported  in,  no,  and  221.  Borgstrom*  found 
well-defined  crystals  about  2  mm.  in  diameter  at  the  boun- 
dary between  the  chrysolite  and  nickel-iron  of  the  Marja- 
lahti  meteorite.  The  dominant  forms  were  in  and  no. 
Combined  with  these  were  331,  311,  and  551  of  which  the 
latter  had  not  previously  been  noted  on  the  mineral.  The 
physical  and  chemical  properties  of  meteoritic  chromite  do 
not  differ  essentially  from  those  of  terrestrial  chromite  ex- 
cept that  meteoritic  chromite  is  sometimes  probably  decom- 
posed by  acids.  This  is  assumed  from  the  content  of  Cr2O3 
often  found  in  the  soluble  portion  of  meteorites.  The  color 
of  meteoritic  chromite  is  in  general  black,  with  sub-metal- 
lic luster;  streak  brown;  non-magnetic  or  only  weakly  so; 
sometimes  very  brittle. 

Analyses  of  meteoritic  chromites  show  the  presence  of 
considerable  alumina  and  magnesia. 

ANALYSES  OF  METEORITIC  CHROMITE 

Cr2O3  A12O3  Fe2O3         FeO  MgO                             Total 

1  65.63  3.78  ....           25.84  4.27  NiO  0.73      100.25 

2  65.49             ••••           33-00  0.40  Si  O2  0.50       99-39 

3  65.01  9.95            18.97  5.06                            98.99 

4  64.91  9.85  17.97  4-96  SiOai.38       99.07 
63.40  5.30  26.30  5.00                           100. 

6  62.71  33.83  ....  96.54 

7  62.00  ....  41.00  ....  ....  103. 

61.39  1-96  30.46  6.70  100.51 

9  59-85  ....  27.93  12.22  100. 

10  56.82  11.36            26.14  5-68  100. 

11  56.70  12.38            27.60  4.00  100.68 

12  52.13  10.25             37-68             100.06 

13  39-40  28.50             31-50  0.60  loo. 

14  24.60             54-50             20.90  100. 

REFERENCES 

1.  Marjalahti.     Borgstrom:    Geol.  Foren.  i.  Stockholm  Forh.,  1908,  30,  331. 
Crystals,  2  mm.  in  diameter. 

2.  Admire.     Tassin:   Proc.  U.  S.  Nat.  Mus.,   1908,  34,  686.     Non-magnetic, 
jet-black  grains  of  brilliant  luster. 

*Geol.  Foren.  i.  Stockholm,  Forh.,  1908,  30,  331. 


166  METEORITES 

3.  Mount  Vernon.     Tassin:  Proc.  U.  S.  Nat.  Mus.,  1908,  34,  685.     Brilliant 
black  crystals. 

4.  Mount  Vernon.     Tassin:  Proc.  U.  S.  Nat.  Mus.,  1908,  34,  686.     Minute, 
rounded,  brownish-black  grains. 

5.  Canyon  Diablo.     Tassin:  Proc.  U.  S.  Nat.  Mus.,  1908,  34,  688.     Small, 
black,  octahedral  crystals  and  rounded  grains. 

6.  Coahuila.     Smith:  Am.  Jour.  Sci.,  1881,  3,  21,  462.     Large  nodule. 

7.  Bjurbole.     Ramsay  and  Borgstrom:     Bull.  Comm.  Geol.  de  Finlande,  1902, 
12,  13.     Black  powder. 

8.  Marjalahti.     Tassin:  Proc.  U.  S.  Nat.  Mus.,  1908,  34,  687.     Brilliant,  blue- 
black  crystals. 

9.  Klein-Wenden.     Rammelsberg:    Ber.  Berlin  Akad.,  1844,  245. 

10.  Shalka.     Foullon:   A.  N.  H.  Wien,  1888,  3,  199. 

11.  Allegan.     Tassin:   Proc.  U.  S.  Nat.  Mus.,  1908,  34,  688.     Blackish-brown 
grains. 

12.  L'Aigle.     Schwager:    Sitzber.  Miinchen  Akad.,  1878,  8,  39-40. 

13.  Sewrukof.     Eberhard:  Arch.  f.  d.  Nat.  Lib.  Ehst.  Kurl.,  1882,  9,  137. 

14.  Lodran.     Rammelsberg:  Abh.  Berlin  Akad.,  1870,  93.     Cohen  states  that 
this  analysis  is  of  doubtful  accuracy     Meteoritenkunde,  i,  246. 

BREUNNERITE 

Determination  of  carbonates  in  meteorites  has  thus  far 
been  confined  to  the  observation  of  small,  transparent  crys- 
tals which  were  isolated  from  the  meteorite  of  Orgueil. 
These  had  characters  which  indicated  that  they  were 
breunnerite,  iron-magnesium  carbonate  (Mg,  Fe)  CO3. 
The  crystals  were  of  rhombohedral  form,  with  angles  of 
IO5°-IO7°  and  exhibited  cleavage  in  three  directions.  They 
showed  weak,  pearly  luster.  They  dissolved  slowly  in  cold 
HC1  and  showed  qualitatively  iron,  magnesia  and  carbonic 
acid.*  The  crystals  were  of  small  size  (]4~Y\  mm.)  and  few 
in  number.  As  Orgueil  is  a  very  porous  meteorite  it  has 
been  suggested  that  this  carbonate  may  have  been  formed 
by  the  action  of  the  terrestrial  atmosphere,  but  as  some 
crystals  were  found  in  the  interior  of  the  meteorite  it  is 
possible  that  they  were  of  primary  origin. 

FELDSPAR 

Minerals  of  the  feldspar  group  are  common  constituents 
of  the  stone  meteorites,  though  less  abundant  than  chrysolite 
and  enstatite.  They  are  chiefly  prominent  in  the  groups  of 
eukrites  and  howardites,  and  among  the  silicates  of  the 
grahamites.  Small  percentages  of  alkalies  found  in  the 
chondrites  are  usually  regarded  as  indicating  the  presence  of 

*Pisani:  Compt.  Rendus,  1864,  59,  135. 


COMPOSITION   OF   METEORITES 


167 


feldspars  in  them  though  the  feldspars  are  difficult  to  detect 
by  optical  means.  The  most  common  and  best  defined 
feldspar  occurring  in  meteorites  is  anorthite.  As  seen  with 
the  naked  eye,  especially  in  the  eukrites,  it  is  usually  nearly 
opaque,  dull,  and  of  a  snow-white  color.  In  some  meteorites, 
however,  it  becomes  more  or  less  transparent  and  has  a 
marked  vitreous  luster.  It  occurs  in  the  form  of  crystals, 
grains,  and  splinters  and  these  are  usually  of  appreciable 
size.  One  crystal  in  Jonzac  measured  I  cm.  in  length. 
The  crystals  are  usually  more  or  less  lath-shaped.  The 


FIG.  51. —  Forms  of  anorthite  from  the  Juvinas  meteorite.     After  Rose,  Lang  and 
Tschermak. 

meteorites  in  which  the  feldspars  are  abundant  usually 
exhibit  the  ophitic  structure  which  is  frequently  observed 
in  diabase.  As  in  terrestrial  rocks,  this  structure  is  due  to 
the  fact  that  the  feldspars  crystallized  before  the  pyroxenes. 
Terminated  crystals  of  anorthite  have  been  found  in  druses 
of  Juvinas  and  have  been  measured  and  described  by  Rose, 
Lang  and  Tschermak.  Their  forms  are  shown  in  the  ac- 
companying figure  (Fig.  51)  of  which  the  first  shows  a  twin, 
the  second  a  tabular  habit,  and  the  third  a  Carlsbad  twin. 
The  forms  observed  were: 


M  oio 
P  ooi 
e  02 1 


T'  TTo 
1'    Tio 

X       101 


O     III 

•  p'  III 


Meteoritic  anorthite  is  soluble  in  hot  HC1.  It  has  been 
isolated  and  analyzed  only  in  the  eukrites  and  grahamites. 
The  following  analyses  have  been  made: 


168  METEORITES 

ANALYSES  OF  ANORTHITE 
Si02          A12O3      Fe2O3         CaO         MgO      Na2O        K2O         Total 


44-38 
46.19 

33.73 

31.26 

3-29 
2-93 

18.07 
16.98 

0.36 

I  .  12 

1.03 
I.I4 

0-33 
0.50 

101  .  19 

IOO.  12 

42.91 

36.76 

17-56 

2-77 

IOO.OO 

42.87 

36.59 

17-50 

2.04 

i  .00 

100.00 

42.02 

37-77 

16.41 

0.96 

97.16 

REFERENCES 


1.  Juvinas.     Rammelsberg:    Pogg.  Ann.,  1848,  73,  588.     Isolated  crystals. 

2.  Stannern.     Rammelsberg:   Pogg.  Ann.,  1851,  83,  592.     Isolated  crystals. 

3.  Petersburg.     Calculated  by  Rammelsberg  from  the  alumina  and  alkali  of 
Smith's  mass  analysis.     Abh.  Berlin  Akad.,  1870,  129. 

4.  Frankfort.     Calculated  by  Rammelsberg  from  the  alumina  and  alkali  of 
Brush's  analysis.     Abh.  Berlin  Akad.,  1870,  131. 

5.  Morristown.     Merrill:   Am.  Jour.  Sci.,  1896,  4,  2,  151.     Analysis  of  0.19 
gram  separated  by  heavy  solution.     Na2O  not  determined. 

Under  the  microscope,  meteoritic  anorthite  usually  shows 
a  large  extinction  angle,  3O°-38°.  Microscopic  inclusions 
are  common.  These  may  be  either  of  rounded  or  elongated 
form  and  may  be  colorless  to  brownish.  Many  are  doubt- 
less glass  inclusions.  They  usually  show  some  regularity  of 
arrangement.  Anorthite  is  estimated  to  constitute  about 
35  per  cent  of  the  meteorites  of  Juvinas  and  Stannern  and 
from  20  to  30  per  cent  of  those  of  Petersburg  and  Frankfort. 
In  the  residue  from  the  solution  in  nitric  acid  of  Bischtiibe, 
a  meteoric  iron,  Kislakowski*  found  about  8  per  cent  of 
siliceous  grains  which  he  regarded  as  anorthite.  Chondri 
made  up  wholly  of  anorthite  have  been  observed  in  several 
meteorites. 

Feldspars  other  than  anorthite  have  rarely  been  isolated 
from  metorites  and  their  presence  can  usually  be  more 
readily  inferred  than  proven.  Where  seen,  their  appear- 
ance under  the  microscope  is  to  be  distinguished  from  that 
of  anorthite  by  their  narrower  and  more  abundant  twinning 
lamellae  and  smaller  extinction  angle.  They  are  not 
attacked  by  hot,  concentrated  HC1,  and  hence  are  found  on 
analysis  in  the  portion  insoluble  in  acids.  Like  anorthite 
they  occur  as  laths,  grains,  and  splinters.  As  laths  they  are 
especially  well  seen  in  some  of  the  grahamites,  having 
been  observed  in  Vaca  Muerta  and  Crab  Orchard.  Where 
feldspar  is  not  very  abundant  as  a  constituent  it  commonly 

*  Bull.  Soc.  Imp.  de  Moscou,  1890,  No.  2,  190-197. 


COMPOSITION   OF   METEORITES  169 

occurs  in  grains,  often  of  small  size  and  not  even  showing 
twinning  lamellae.  In  such  cases  the  grains  exhibit  un- 
dulatory  extinction.  Plagioclase  grains  were  isolated  by 
Prendel  from  Zabrodje  and  Grossliebenthal  which  showed 
in  Zabrodje  extinction  angles  of  12°  and  2°,  indicating  felds- 
par of  the  composition  Ab6Ani  and  in  Grossliebenthal  angles 
of  8°  and  i°  indicating  feldspar  of  the  composition,  Ab4Ani. 
In  the  residue  after  dissolving  the  Toluca  iron  in  HC1, 
Laspeyres  found  plagioclase  grains  showing  twinning  lamel- 
lae. Plagioclase  other  than  anorthite  has  not  been  isolated 
from  meteorites  for  chemical  analysis  but  the  following  com- 
positions have  been  calculated  from  mass  analyses: 

ANALYSES  OF  METEORITIC  PLAGIOCLASES 

Si02         A1203          CaO         Na20       K2O         Total 
i 64.97        22.06        3.01          9.96         100 

2 63.50  22.20  4.00  9-20  I.  10  100 

3 61.85         24.09        5.25  8.81         ioo 

4 53-17        29.51       11.55          4-33         i-44         ioo 

REFERENCES 

1.  Hessle.     Lindstrom:   Bihang  Svenska  Vet.  Akad.  Stockholm,  1869,  8,  723. 

2.  Hvittis.     Borgstrom:    Die  Met.  von  Hvittis  u.  Marjalahti.  Helsingfors., 
1903,  32.     Calculated  to  ioo  after  deducting  intermixed  chrysolite. 

3.  Gopalpur.     Tschermak:   Sitz.  Wien  Akad.,  1872,  65,  I,  143-144. 

4.  Tennasilm.     Schilling:    Archiv.  fur  Naturkunde  Liv.  Ehst.  u.  Kurlands, 
1882,  i,  9,  113. 

The  first  three  feldspars  are  oligoclase,  having  the  re- 
spective compositions,  Ab6An,  Ab4An,  and  Ab3An.  No.  4 
is  labradorite,  Ab2An3.  The  feldspars  of  a  large  number  of 
meteorites  were  studied  optically  by  H.  Michel.*  He  found 
the  feldspar  of  the  eukrites  and  howardites  to  be  largely 
anorthite  while  that  of  the  chondrites  was  chiefly  oligoclase. 
Considering  the  chondrites  alone,  the  white  chondrites  were 
found  to  have  abundant  feldspar  while  the  black  chondrites 
were  free  from  it.  Other  chondrites  had  varying  amounts 
according  as  they  approached  either  one  of  these  classes. 
In  the  chondrite  of  Waconda  containing  light  and  dark  por- 
tions the  amount  of  feldspar  differed  in  each  as  if  they  were 
separate  meteorites.  In  many  chondrites  in  which  the  pre- 
sence of  a  feldspar  was  indicated  by  chemical  analysis,  glass 
took  the  place  of  the  expected  feldspar.  It  was  apparent, 

*Tsch.  Min.  u.  Pet.  Mitt.,  1912,  31,  563-658. 


170  METEORITES 

therefore,  that  the  glass  had  the  composition  of  feldspar  of 
which  it  may  have  been,  according  to  this  author,  an  alter- 
ation product,  although  a  primary  origin  is  entirely  possible. 

MASKELYNITE 

A  mineral  of  hitherto  unknown  characters  was  found  by 
Tschermak*  making  up  22^/2  per  cent  of  the  meteorite  of 
Shergotty.  It  was  colorless,  isotropic,  transparent,  of 
vitreous  luster,  and  conchoidal  fracture.  Hardness  6; 
specific  gravity  2.65.  Before  the  blowpipe  it  fused  in  thin 
splinters  to  a  clear,  colorless  bead.  The  fine  powder  was 
slightly  decomposed  by  hydrochloric  acid.  The  mineral 
occurred  in  feldsparlike  laths  bounded  by  straight  lines. 
Lines  parallel  to  their  lengths  gave  these  laths  an  appearance 
like  plagioclase,  but  the  cleavage  of  plagioclase  was  lacking. 
Analysis  of  the  mineral  after  deduction  of  4.7  per  cent  iron 
oxide  which  was  ascribed  to  included  magnetite,  gave,  when 
calculated  to  100,  the  composition: 

SiO2      A12O3      CaO     Na20     K2O 
56.3       25.7        n.6       5.1        1.3  =  100 

This  corresponds  to  a  plagioclase  composed  of.  51.75  per 
cent  albite  and  48.25  per  cent  anorthite,  if  K2O  be  omitted 
and  the  analysis  be  calculated  to  100. 

To  this  mineral  Tschermak  gave  the  name  maskelynite  in 
honor  of  N.  Story-Maskelyne.  Tschermak  regarded  it  a 
fused  feldspar  At  the  same  time  by  Foullon  and  later  by 
several  observers  a  similar  mineral  was  found  forming  an 
accessory  constituent  in  many  of  the  chondrites.  It  was 
described  by  Cohen, f  in  Madrid,  as  being  in  the  form  of 
small,  elongated  or  rounded  particles  lying  among  the 
essential  minerals  and. taking  part  in  the  constitution  of  the 
chondri.  The  grains  had  a  diameter  of  o.i  mm.  or  more, 
were  irregularly  bounded,  had  weak  double  refraction  and 
occasional  indulatory  extinction.  The  index  of  refraction 
was  about  that  of  Canada  balsam. 

*Sitz  Wien  Akad.,  1872,65,  127-131. 

fMitth.  nat.  Verein  Neu-Vorp.  u.  R.,  1896,  28,  103-105. 


COMPOSITION   OF   METEORITES  171 

Winchell*  found  in  Fisher  in  the  midst  of  an  isotropic 
substance,  portions  which  were  doubly  and  more  highly 
refracting  and  which  showed  lamellae  resembling  those  of 
plagioclase.  The  axial  angle  was  15°.  Both  the  isotropic 
and  doubly  refracting  portions  gave  the  same  qualitative 
composition.  Winchell  regarded  the  isotropic  substance  as 
glass  from  which  the  anisotropic  mineral  had  crystallized. 
This  anisotropic  mineral  he  regarded  as  maskelynite.  While 
Tschermak  regarded  maskelynite  as  a  fused  feldspar,  Groth 
and  Brezina  consider  it  a  distinct  mineral  allied  to  leucite. 
Its  exact  nature  is  yet  to  be  determined. 

ORTHORHOMBIC  PYROXENES 
ENSTATITE,  BRONZITE  AND  HYPERSTHENE 
Chladnitt,  Piddingtonite,  Fictorite,  Shepardite 

Orthorhombic  pyroxenes  rank  third  in  quantity  among 
the  constituents  of  meteorites,  being  exceeded  only  by  nickel- 
iron  and  chrysolite.  Together  with  chrysolite  they  form 
almost  the  entire  substance  of  the  great  group  of  chondritic 
stone  meteorites  and  are  also  an  important  ingredient  in  the 
howardites,  rodites,  amphoterites,  mesosiderites,  and  gra- 
hamites.  Enstatite  constitutes  one  meteorite,  Bishopville, 
almost  alone,  and  hypersthene  is  practically  the  sole  con- 
stituent of  Manegaum,  Ibbenbiihren,  and  Shalka.  These 
pyroxenes  are  colorless  to  snow-white  in  enstatite  and  pre- 
sent various  shades  of  gray,  green,  and  brown  in  bronzite 
and  hypersthene.  Inclusions  may  also  darken  the  color. 
Often  a  color  like  that  of  chrysolite  is  exhibited  and  partly 
for  this  reason  the  recognition  of  orthorhombic  pyroxene 
was  not  made  until  late  in  the  study  of  meteorites.  Other 
distinguishing  characters  of  the  orthorhombic  pyroxenes  as 
seen  in  meteorites  are  a  frequent  fibrous  structure,  prismatic 
cleavage,  pinacoidal  parting,  straight  extinction,  low  inter- 
ference colors,  prismatic  habit,  and  little  or  no  solubility  in 
acids.  The  first  to  detect  the  occurrence  of  orthorhombic 
pyroxene  in  meteorites  was  Langf  who  determined  the 

*  Amer.  Geol.,  1897,  20,  316-317. 
fSitz.  Wien  Akad.,  1869,  59,  2,  848-856. 


172 


METEORITES 


pyroxene  in  Steinbach  previously  regarded  as  monoclinic  to 

be  orthorhombic. 

By  his  investigations  and  those  of  others  the  following 
crystal  forms  have  been  determined 
on  the  orthorhombic  pyroxenes  of 
meteorites: 

a..ioo     77.. 140     g.  .021      ^..252 

b .  .010      £..320      fl.  .031       C..2I2 

C..OOI     z..2io     ^..201  y. .432 

m..no     8.  .  520    /.  .502  i..2ii 

a. .230     X..3IO     O..III  ^..623 

X .  .221  f..4I2 


FIG.  52. — Enstatite    from    the        ' 

Steinbach      meteorite.       n..l2O      <?..O23       ^..232     ^..323 

p. .250       t.  .Oil       p. .121     t    .421 

Axes  a  :  b  :  c'  =  0.9702  :  I  :  0.5709. 

Fig.  52  shows  the  habit  of  the  pyroxene  observed  by  Lang 
although  the  figure  is  more  or  less  ideal.  Weisbach* 
observed  the  form  shown  in  Fig.  53  in  Rittersgriin  which  is 
of  the  same  fall  as  Steinbach.  The  stone  meteorites  of 
Bustee,  Lodran,  Manegaum,  Massing,  Mocs,  Misshof,  and 
the  iron  of  Bendego  are  other 
meteorites  from  which  simple 
forms  of  orthorhombic  pyroxene 
have  been  isolated  and  measured. 
The  recognition  of  orthorhombic 
pyroxene  in  Breitenbach  by  Lang 
led  to  the  appreciation  of  its 
wide  distribution  and  our  present 
knowledge  that  it  is  one  of  the 
most  abundant  of  meteoritic 
minerals.  Optical  characters  and 
chemical  analyses  afford  the  chief 
means  for  recognizing  its  presence 
as  its  occurrence  is  usually  in  the 
form  of  small  individuals.  Yet, 
as  has  been  remarked,  some  mete- 

*Neues  Jahrbuch,  1882,  2,  253. 


FIG.  53.  Enstatite  from  the 
Steinbach  (Rittersgriin) 
meteorite.  After  Weisbach. 


COMPOSITION   OF   METEORITES 


173 


prite  falls  consist  alone  of  this  mineral.  Previous  to  the 
recognition  of  the  orthorhombic  pyroxene  the  substance  of  the 
meteorites  composed  of  it  almost  wholly  had  frequently  been 
regarded  as  new  minerals  and  had  received  the  names  chlad- 
nite  and  shepardite  in  Bishopville,  piddingtonite  in  Shalka, 
and  victorite  in  Copiapo.  In  the  chondritic  meteor- 
ites orthorhombic  pyroxene  enters  largely  into  the  forma- 
tion of  the  chondri.  The  structure  of  the  chondrus  is  usually 
polysomatic  and  the  habit  of  the  individuals  is  largely  pris- 
matic to  fibrous.  An  eccentric  rayed  arrangement  is  also 
highly  characteristic.  The  fibres  may  be  so  fine  as  to  appear 
compact  and  rarely  may  be  irregularly  arranged.  Inter- 
growths  with  chrysolite  forming  chondri  are  common,  and 
occasionally  association  with  monoclinic  pyroxenes  may  be 
observed.  At  times  the  orthorhombic  pyroxene  forms  a 
network  cementing  larger  crystals. 

The  following  analyses  have  been  made  of  orthorhombic 
pyroxenes  mechanically  isolated  from  meteorites: 


ANALYSES 

OF  ORTHORHOMBIC  PYROXENES 

OF  METEORITES 

Si02 

MgO 

CaO 

FeO 

Fe2O3  A12O3 

K2O      Na20 

Total 

j 

55  -7^ 

41  .85 

3.89 

101  .50 

2a. 

57.60 

40.64 

1.44       .... 

0.39      0.91 

100.98 

2b. 

57-58 

39-33 

2.06 

o  .  48       

0.57      0.67 

100.69 

2C. 

58-44 

38.94 

1.68 

1.18 

0.33      0.36 

100.93 

3a. 

59-97 

39-33 

o  .  40       .... 

....      0.74 

100.44 

3b. 

57-52 

34.80 

0.66 

MnO 

0.20 

•    1.25       2.72 

0.70      1.14 

98.99 

4 

59-05 

37.10 

0.98 

FeO 

0.90 

•    ....       1.09 

o  .  47      o  .  68 

100.27 

5 

55-35 

32-85 

0.58 

12.13 

....       0.60 

....       .... 

101.51 

6 

57-49 

25-78 

2.12 

10.59 

f  MnO  \         g 

I  0.49  / 

i-45 

IOO.OO 

7 

56.05 

^o  85 

J-2     A  A 

ioo.  34 

8a. 

53-07 

JW        W  J 

28.55 

0.90 

0.47 

....          O.22 

IOO.OO 

8b. 

55    55 

27  71 

O   OQ 

l6-53 

O   Q2 

ioo.  82 

Be. 

j  j   j  j 
52.78 

/        /  J 

24.18 

**y 
O   CO 

22  .43 

....              w  .  *yt* 

QQ    80 

93. 

J           1 

54-47 

T 

26.12 

^    3^^ 

1-39 

17.15 

W}i.'o6 

ss  *  ^s 

100.47 

9b. 

54-51 

26.43 

1.04 

17-53 

\^g]  l'26 

101.06 

loa. 

54-22 

23  .57 

I  .  CI 

2O.  70 

IOO.OO 

lob. 

55  .70 

22.80 

J 

I  .12 

20.  54 

100.36 

ii 

51.61 

16.05 

J 

3.68 

24-54 

....       7-36 

103.24 

0  =  3.20—  3 

•43 

174  METEORITES 

REFERENCES 

1.  Copiapo.     Meunier:  Cosmos,  Paris,  1869,  5,  583-585. 

2.  Bustee..    Maskelyne:   Phil.  Trans.  Roy.  Soc.  London,  1870,  160,  206.     The 
iron  oxide  obtained  was  in  part  ascribed  to  intermixed  nickel-iron,  the  lime  to 
intergrown  augite.     (a)  Dark-gray  tabular  crystals,     (b)  Translucent  gray  crys- 
tals,    (c)  Transparent  crystals. 

3.  Bishopville.     (a)  Smith,  Am.  Jour.  Sci.,  1864,  2,  226.     Mean  of  two  analyses, 
(b)   Rammelsberg,  Berlin  Akad.,   1861,  898.     Probably  a  little  plagioclase  was 
intermingled. 

4.  Hvittis.     Borgstrom:   Helsingfors,  1903,  30. 

5.  Lodran.     Tschermak:  Sitzb.  Wien  Akad.,  1870,  61,  2,  471.     Some  chrysolite 
and  perhaps  anorthite  were  mixed  with  the  substance  analyzed. 

6.  Rittersgriin.     Winkler:    Nova   acta  Akad.   Halle,    1878,   40,  No.   8,   365. 
Mean  of  two  analyses.     Calculated  to  100  after  deducting  0.98  per  cent  chromite. 

7.  Breitenbach  (same  as   Rittersgriin).     Maskelyne:     Phil.  Trans.  Roy.   Soc. 
London,  1870,  160,  361.     Mean  of  two  analyses. 

8.  Shalka.     (a)   Foullon:   A.  N.  H.  Wien,  1888,  3,   198.     Calculated   to  100 
after  deducting  0.39  per  cent -troilite  and  1.74  per  cent  chromite.     (b)  Rammels- 
berg, Berlin  Aka^.,  1870,  319,0.33  per  cent  chromite  deducted,     (c)  Maskelyne: 
Phil.  Trans.  Roy.  Soc.  London,  1870,  367.     Mean  of  two  analyses. 

9.  Ibbenbuhren.     Rath:    Berlin  Akad.,   1872,  34.     (a)   Light-gray  to  white 
grains  of  the  ground  mass,     (b)  Light  yellowish-green  larger  grains. 

10.  Manegaum.     Maskelyne:    Phil.  Trans.  Roy.  Soc.  London,  1870,  212-213. 

(a)  Ground  mass.     Calculated  to  100  after  deducting  1.03   per  cent  chromite. 

(b)  Pale  yellowish-green  grains. 

11.  Sierra  di  Deesa.     Meunier:   Cosmos,  1869,  584. 

A  marked  feature  of  the  composition  shown  by  these 
analyses  is  the  lack  of  an  intermediate  content  of  iron. 
The  transition  is  sudden  from  a  composition  in  which  MgO 
i-s  practically  the  only  base  to  one  in  which  a  considerable 
percentage  of  FeO  appears.  In  other  words  enstatite  and 
hypersthene  occur  without  intervening  bronzite.  Hence 
though  the  orthorhombic  pyroxene  of  meteorites  is  usually 
spoken  of  as  bronzite,  that  mineral,  if  the  limits  used  by 
Dana  (up  to  12-15  per  cent  FeO)  are  adopted,  seems  to  be 
rarely  present.  The  pyroxene  of  Breitenbach  which  Lang 
called  bronzite  possesses  the  characters  of  hypersthene  in 
being  optically  negative  and  in  having  the  bisectrix  _L  to  a. 
Its  dispersion,  however,  was  p<v  or  that  of  bronzite.  The 
axial  angle  was  98°. 

Cohen*  suggests  that  a  rough  approximation  of  the 
amount  of  iron  in  the  pyroxene  of  most  meteorites  can  be 
obtained  by  heating  the  powder.  If  the  substance  is  rich 
in  iron,  a  brownish  or  brownish-yellow  color  is  obtained  on 
heating,  whereas,  if  iron  is  absent  or  nearly  so,  only  a  pale 

*Meteoritenkunde,  Heft  II,  280. 


COMPOSITION   OF   METEORITES  175 

brown  or  no  change  will  be  observed.  For  such  a  test  any 
chrysolite  in  the  powder  should  first  be  removed  by  a  heavy 
solution.  Enstatite,  bronzite,  and  hypersthene  accompany- 
ing one  another  were  observed  by  Prendel*  in  Grosslieben- 
thal.  He  found  enstatite  and  bronzite  characterizing  the 
chondri,  and  hypersthene  the  ground  mass.  "  The  bronzite 
contained  glass  inclusions  while  the  characteristic  form  of 
the  hypersthene  was  that  of  needles  arranged  parallel  to 
their  vertical  axes. 

The  portion  of  the  chondrites  and  mesosiderites  insoluble 
in  acid  usually  is  made  up  chiefly  of  orthorhombic  pyroxenes. 
Hence  analyses  of  this  portion  practically  give  the  composi- 
tion of  these  pyroxenes.  The  following  analyses  selected 
by  Cohenf  illustrate  compositions  obtained  by  this  method. 

ANALYSES  OF  INSOLUBLE  SILICATES  FROM  METEORITES 


I 

Si02 

57.80 

MgO 

39-22 

CaO 

FeO 
0.91 

A12O3     K2O 

2.07 

Na2O 

Sum 

IOO 

2 

56.74 

24.05 

y 

.41 

8 

.04 

5-63      0.25 

i'88 

IOO 

3 

55-79 

24.99 

3 

.40 

8 

•79 

4.90         0.12 

2.01 

IOO 

4 

57-37 

23.54 

3 

8 

•03 

5.07         0.23 

1-38 

(MnO\ 
10.63    / 

99- 

66 

5 

56.20 

24.19 

3 

•37 

9 

•27 

4.38         0.92 

2.22 

JPAl 
\  0.07  / 

IOO. 

55 

6 

58.42 

28.04 

3 

.04 

10 

•99 

I  .12          .... 

101  . 

61 

7 

57-8i 

24.97 

5 

10 

•99 

0.23 

0.84 

IOO. 

15 

8 

57.60 

23-97 

5 

.70 

ii 

•24 

0.43 

1.24 

IOO. 

18 

9 

52.90 

24.82 

10.00 

5.96         0.48 

2.98 

jMnO   1 

97- 

45 

10 

54-42 

29.  II 

2 

.46 

14 

•03 

....           .... 

100. 

02 

.  T 

c6   71 

2C  qq 

T 

77 

I  ^ 

.  21 

232 

IOO 

I  2 

y*  '  i 
C7    74. 

J  '  /  s 

22    23 

c 

•  /  / 
CA 

It 

17 

C    32 

IOO 

13 

JJ   •   /T 

55.98 

26.08 

. 

'  JT 

x  J 

-    / 
.89 

3-05 

IOO 

H 

51.10 

27.70 

17 

.20 

2.83          .... 

98. 

83 

15 

52.56 

20.28 

5 

O2 

16 

.18 

4.15 

I  .8l 

IOO 

16 

53.82 

23  -41 

i  . 

77 

18 

-65 

2-35 

IOO 

/  MnO 

17 

54.02 

23-45 

tr. 

18 

.  10 

2.30        tr. 

1.58 

\o.36 

99- 

81 

18 

54-12 

24.50 

21 

•05 

o  .  03       .... 

0.09 

99- 

79 

19 

56.66 

20.84 

23 

•55 

101. 

05 

20 

50-52 

8.09 

9 

27 

27 

•94 

4.18         tr. 

tr. 

IOO. 

REFERENCES 

1.  Molina.     Meunier:  Ann.  Chem.  Phys.,  1869,  4,  17,  12. 

2.  Cape  Girardeau.     Dana  and  Penfield:    Am.  Jour.  Sci.,  1886,  3,   32,   230. 
1.67  per  cent  chromite  deducted. 

3.  Salt  Lake  City.     Dana  and  Penfield:   Am.  Jour.  Sci.,  3,  32,  228.     1.71  per 
cent  chromite  deducted. 

*Mem.  Soc.  Nat.  Russie,  Odessa,  1893,  18. 
fMeteoritenkunde  Heft  I,  283. 


176  METEORITES 

4.  Stalldalen.     Lindstrom:    Ofversigt  Kongl.  Vetenskaps  Akad.    Stockholm, 
1877,  No.  4,  37. 

5.  Pultusk.     Rammelsberg:    Monatsber.  Berlin  Akad.,  1871,  451.     Mean  of 
two  analyses. 

6.  Mighei.     Meunier:     Comptes  Rendus,  1889,  109,  977. 

7.  Rochester.     Smith:   Am.  Jour.  Sci.,  1877,  14,221.     0.15  per  cent  chromite 
deducted. 

8.  Cynthiana.     Smith:  Am.  Jour.  Sci.,  1877,  14,  226.     0.56  per  cent  chromite 
deducted. 

9.  Aussun.     Harris:   Inaug.  Diss.  Gottingen.,  1859,  49. 

10.  San  Emigdio.     Whitfield:   Bull.  U.S.  G.  S.,  1891,  No.  78,97.     1.32  per 
cent  chromite  deducted. 

11.  Zsadany.     Cohen:    Verhandl.  Nathist.  med.  Ver.  Heidelberg,  1878,  161. 

12.  Richmond.     Rammelsberg:    Monatsber.  Berlin  Akad.,  1871,  456. 

13.  Hainholz.     Rammelsberg:    Monatsber.  Berlin  Akad.,  1871,  323. 

14.  Roda.     Pisani:    Comptes  Rendus.,  1874,  1508. 

15.  Gnadenfrei.     Lasaulx:    Monatsber.  Berlin  Akad.,  1879,  769. 

16.  Llano  del  Inca.     Eakins:  Bull.  U.  S.  G.  S.,  1891,  No.  78,  97.     1.32  per  cent 
chromite  deducted. 

17.  Waconda.     Smith:    Am.  Jour.  Sci.,  1877,  3,  13,  212. 

18.  Estherville.     Smith:  Am.  Jour.  Sci.,  1880,  3,  19,  462. 

19.  Sokobanja.     Losanitsch:      Ber.  deutsch.  chem.  Gesell.  Berlin,  1878,  n,  98. 
o.i  i  per  cent  chromite  deducted. 

20.  Tadjera.     Meunier:    Ann.  Chim.  Phys.,  1869,  4,  17,  16.     0.18  per  cent 
chromite  deducted. 

CLINOENSTATITE  AND  CLINOHYPERSTHENE 
The  name  clinoenstatite  was  proposed  by  Wahl*  to  desig- 
nate a  monoclinic  magnesian  pyroxene  occurring  in  stony 
meteorites.  The  presence  of  such  a  pyroxene  seems  first  to 
have  been  noted  by  Fouque  and  Levyf  but  Allen,  Wright, 
and  Clement{  were  the  first  to  give  it  extended  study.  In 
Bishopville  the  latter  authors  found  the  mineral  forming 
parallel  intergrowths  with  ordinary  enstatite,  it  being 
marked  chiefly  by  its  oblique  extinction  c  :  c=2i°  8'. 
Similar  intergrowths  were  produced  artificially  by  these 
authors  by  rapidly  cooling  a  molten  mass  of  pure  magne- 
sium silicate.  The  slower  the  cooling  the  greater  the  quan- 
tity of  clinoenstatite  obtained.  They,  therefore,  concluded 
that  the  presence  of  these  intergrowths  in  meteorites  indi- 
cated rapid  cooling.  In  their  first  paper  these  authors  stated 
that  the  enstatite  of  the  meteorite  was  all  changed  to  the 
monoclinic  form  on  heating  to  1450°.  In  a  later  paper,  how- 
ever,! they  stated  that  at  about  1365°  clinoenstatite  is  trans- 

*Tsch.  Min.  u.  Petr.  Mitth.,  1907,  26,  121. 
fBull.  Soc.  Min.,  1881,  279. 
JAm.  Jour.  Sci.,  1906,  4,  22,  385-438. 
§Am.  Jour.  Sci.,  1909,  4,  27,  45. 


COMPOSITION   OF   METEORITES  177 

formed  into  an  orthorhombic  form  quite  distinct  from  en- 
statite  and  unknown  in  nature.  In  clinoenstatite  the  plane 
of  the  optic  axes  is  normal  to  the  plane  of  symmetry  and 
not  in  the  plane  of  symmetry  as  in  ordinary  enstatite.  The 
specific  gravity  of  the  artificial  clinoenstatite  was  3.192. 
In  addition  to  clinoenstatite  there  occur  in  meteorites 
according  to  Wahl  clinobronzite  and  clinohypersthene. 
They  differ  from  clinoenstatite  just  as  their  corresponding 
orthorhombic  homologues  do.  Such  pyroxenes,  according  to 
Wahl,  especially  characterize  the  chondrites,  and  much  of 
what  has  previously  been  regarded  as  other  monoclinic 
pyroxenes,  such  as  diopside  and  augite,  may  belong  to  the 
monoclinic  forms  of  the  enstatite-hypersthene  group. 

MONOCLINIC  PYROXENES 

Monoclinic  pyroxenes  have  been  described  from  a  number 
of  meteorites  and  form  an  essential  constituent  of  the 
eukrites,  howardites,  bustites,  ureilites,  shergottite  and 
angrite,  and  are  an  accessory  constituent  in  the  grahamites, 
mesosiderites,  and  some  chondrites.  Except  for  diopside 
in  the  meteorites  of  Bustee  and  El  Nakhla  the  monoclinic 
pyroxenes  have  usually  been  referred  to  augite,  but  their 
chemical  composition  makes  it  unlikely  that  this  mineral 
is  as  common  as  has  been  reported,  since  chemically  the 
composition  of  these  pyroxenes  is  nearer  that  of  heden- 
bergite.  The  monoclinic  pyroxenes  usually  occur  as  grains 
and  splinters  without  well-defined  outlines.  These  grains 
are  generally  brown  or  in  transmitted  light  brownish-gray 
and  show  little  or  no  pleochroism.  Prismatic  cleavage  is 
present  and  occasionally  a  pinacoidal  cleavage  correspond- 
ing to  that  of  diallage.  Some  writers  regard  diallage  as  fre- 
quently present  on  account  of  this  cleavage  but  according  to 
Cohen  it  is  in  no  case  so  well-marked  as  to  make  the  simi- 
larity to  terrestrial  diallage  certain.  Simple  twins  or  twin- 
ning lamellae  on  the  plane  of  the  orthopinacoid  were  noted 
by  Lane  and  Patton  in  the  augite  of  Llano  del  Inca.  Part- 
ing parallel  to  the  base  is  also  common.  In  the  chondritic 
meteorites  the  monoclinic  pyroxene  is  generally  of  a  greenish 
color,  shows  repeated  twinning  and  appears  partly  in  grains 


178  METEORITES 

and  partly  in  laths.  It  occurs  partly  alone  and  partly  ac- 
companied by  chrysolite,  orthorhombic  pyroxene,  or  glass. 
Where  monoclinic  pyroxenes  occur  in  crystals  they  often 
contain  inclusions  of  brownish  glass  and  black  grains.  These 
are  sometimes  arranged  parallel  to  the  base  so  as  to  give  a 
black-lined  effect.  In  Nowo-Urei  black  grains  are  arranged 
peripherally  in  the  pyroxene. 

DIOPSIDE 

Diopside  was  found  by  Maskelyne  in  Bustee  in  the  form 
of  splinters  and  crystal  grains,  chiefly  accompanying  con- 
cretions of  oldhamite.  The  color  of  the  grains  was  gray  to 
light  violet.  The  forms  ooi,  100,  and  no  were  determined 
and  the  presence  of  the  negative  unit  pyramid  was  indicated. 
The  prismatic  angle  lay  between  85°  8'  and  86°  20'.  The 
angle  of  extinction  was  52^°,  the  axial  plane  perpendicular 
to  the  edge  ooi  A  100.  In  the  zone  ooi  :  oil  pleochroism 
was  observed,  the  color  on  the  clinopinacoid  being  reddish 
violet  to  slate  color.  Prismatic  cleavage  and  parting  parallel 
to  loo  were  observed  as  well  as  a  microscopic  parting  re- 
sembling that  of  diallage.  Black,  needle-like  inclusions 
parallel  to  100  and  inclusions  of  enstatite  parallel  to  the  base 
were  present.  The  mean  of  two  analyses  gave  the  following: 
SiO2  Fe2O3  CaO  MgO  "  Na2O  Li2O 
55.49  0.54  19.98  23.33  0-55  tr.  =99.89 

This  gives  a  ratio  of  CaO  :  MgO  =  I  :  I  .  635.  The 
mineral  is  thus  more  magnesian  than  terrestrial  diopside. 
Maskelyne  was  inclined  to  ascribe  this  content  of  magnesia 
to  the  included  enstatite,  but  Cohen  thinks  its  amount 
insufficient.  Of  the  meteorite  of  El  Nakhla,  according  to 
Berwerth,*  diopside  forms  an  important  part,  in  fact,  about 
three-fourths.  It  occurs  in  this  meteorite  in  the  form  of 
transparent,  grayish  green  grains  and  prisms  up  to  I  mm. 
in  length.  Only  prismatic  and  pinacoidal  planes  were 
observed.  Twinning  on  100  was  frequent.  The  optical 
character  was  positive  and  the  plane  of  the  optic  axes  was 
in  the  symmetry  plane. 

Some  minute  plates  of  a  straw-yellow  color,  which  Rose 

*Tsch.  min..u.  pet.  Mitth.,  1912,  Bd.  31 


COMPOSITION   OF   METEORITES 


179 


observed  in  Juvinas  and  which  Rammelsberg  referred  to 
titanite,  were  regarded  by  Tschermak  as  diopside.  Owing 
to  a  fine  lamellar  structure  he  regarded  them  as  paramorphs 
after  augite.  Tschermak  also  referred  to  diopside  some  grayish 
green  crystals  in  Mocs  which  differed  from  the  accompany- 
ing orthorhombic  pyroxene  in  color  and  optical  characters. 

Tschermak  described  and  figured  from  druses  of  Juvinas 
a  crystal  of  augite  having  a  diopside-like  habit  which  Cohen 
suggested*  was  probably  diopside.  This 
crystal  showed  the  following  forms :  #(100), 
fc(oio),  c(ooi),  w(no),  /(3io),  *(5IQ), 
w(in)  and  0(221).  It  is  shown  in  Fig.  54. 
The  extinction  angle  on  the  clinopinacoid 
was  52°  10'.  A  structure  of  numerous  thin 
lamellae  parallel  to  the  base  probably  in- 
dicated twinning.  Inclusions  of  black  or 
brown  rounded  inclusions  generally  ar- 
ranged parallel  to  the  base  were  observed 
passing  to  a  dust-like  fineness.  The 
brown,  transparent  inclusions  were  deter- 
mined to  be  glass.  Emergence  of  an  optic 
axis  was  noted  on  orthopinacoidal  sections  as  in  the  Ala 
diopside. 

HEDENBERGITE 

It  has  already  been  remarked  that  the  chemical  com- 
position of  several  meteoritic  pyroxenes  reported  to  be 
augite  more  nearly  resembled  hedenbergite  since  alumina 
was  almost  entirely  lacking.  A  mechanically  isolated 
pyroxene  from  Shergotty  also  gave  Tschermak  a  similar 
result.  The  analyses  follow: 


FIG.  54. —  Diopside? 
from  the  Juvinas 
meteorite.  After 
Tschermak. 


Si02         A12O3 


ANALYSES  OF  HEDENBERGITE 
FeO        MnO       CaO      MgO     K,O 


Na20 


la. 
ib. 

23. 
2b. 

3 
4 


52.50 
52.88 

49-31 
50.40 

52-94 

50.25 


0.24 


31.06 
30.70 

28.24 

31-64 
29.76 
31.62 


1-25 


5-73 
6.32 
8.18 
7.62 

5-44 
6.96 


10. 06 
10.10 
9  94 
10.34 
11.86 
11.17 


0.41 
o.io      0.35 


56.05       2.55        7.21       0.38        2.33       31.48 


52.34       0.25       23.19         tr. 
*Meteoritenkunde,  Heft  I,  293. 


10.49       I4-29 


tr. 


Total 

100. 
100. 
100. 
100. 
100. 
100. 
100. 

100.56 


180 


METEORITES 


REFERENCES 

1.  Juvinas.     Rammelsberg:     (a)    Siliceous    portion    undecomposed    by    acid. 
Calculated   to    100  after  deducting  2.13    per  cent   chromite   and   0.16   per  cent 
TiCV     Pogg.  Ann.,  1848,  73,  589.     (b)  Calculated  from  the  composition  of  the 
siliceous  portion  after  deducting  calculated  anorthite.     Abh.  Berlin  Akad.,  1870, 
129. 

2.  Stannern.     Rammelsberg:    (a)  Siliceous  portion  not  decomposed  by  acid. 
Calculated  to  100  after  deducting  0.83  per  cent  chromite.     Pogg.  Ann.,  1851,  83, 
592.     (b)  Calculated  like  ib.     Same  reference. 

3.  Petersburg:     Calculated    by    Rammelsberg    from    Smith's    mass    analysis. 
Abh.  Berlin  Akad.,  1870,  129. 

4.  Luotolaks:     Calculated    by    Rammelsberg    from    Arppe's    analysis.     Abh. 
Berlin  Akad.,  1870,  135. 

5.  Nowo-Urei:    Calculated  by  Jerofejeff  and  Latschinoff  from  analysis  of  the 
undecomposed   siliceous   portion.     Verhandl.   russ.   Min.   Gesell.,   St.   Petersburg, 
1888,  24,  17,  23. 

6.  Shergotty:  Tschermak.  Sitzb.  Wien  Akad.,  1872,  65,  126,  and  Tsch.  Mirth., 
1872,  88. 

From  the  above  it  seems  likely  that  this  variety  of  pyrox- 
ene is  a  common  constituent  of  meteorites  and  that  much 
that  has  hitherto  been  called  augite  should 
be  referred  to  it. 

AUGITE 

Augite  has  been  determined  both  by 
optical  and  chemical  means  in  only  one 
meteorite,  Angra  dos  Reis.  Of  this  mete- 
orite, accordingto  Ludwig  and  Tschermak* 
augite  constitutes  about  93  per  cent.  It 
takes  the  form  of  grains  of  a  dark  brown 
color  showing  red  by  transmitted  light. 
It  shows  well-marked  pleochroism,  a  being 
pale  yellowish-green,  b  carmine-red,  and  c 

The  maximum  extinction  angle  is  37°. 
There  are  inclusions  of 


FIG.  55. — Augite  from 
the  Juvinas  meteor- 
ite. After  Rose. 


carmine-like  red. 
Cleavage  straight  or  undulating, 
glass,  rounded  grains  of  chrysolite  and  angular  ones  of 
troilite.  The  glass  is  of  a  brown  color.  The  augite  is  con- 
siderably attacked  by  warm  hydrochloric  acid.  Analysis 
showed  the  following  composition : 

SlO2       A1203      Fe2O3     FeO        CaO     MgO    K2O    Na2O    TiO2      Total 

45.28         9.40         0.33         7.48         24.83      9.63       0.20      0.28       2.57          =100 

TiO2  is  regarded  as  replacing  Si02. 

From  druses  in  Juvinas  Rose  obtained  crystals  showing 
typical  augite  forms,  a  drawing  of  which  is  shown  in  Fig.  55. 

*Tsch.  Min.  u.  Pet.  Mitth.,  1909,  28,  114. 


COMPOSITION   OF   METEORITES  181 

The  forms  observed  were  <z(ioo),  &(oio),  ra(iio),  J"(in)  and 
0(221).* 

WEINBERGERITE 

A  black  mineral  occurring  in  spherical  aggregates  of 
radiating  fibers  was  found  by  Berwerthf  in  the  iron  meteor- 
ite of  Kodaikanal.  From  analyses  he  obtained  the  formula 
NaAlSiO4  +  3  FeSiO3.  The  optical  properties  indicated 
orthorhombic  crystallization.  Berwerth  gave  the  mineral 
the  name  weinbergerite.  Its  occurrence  has  not  been  noted 
in  any  other  meteorite. 

FORSTERITE 

This  mineral  occurs  in  rounded  grains  in  the  iron  of 
Tucson.  The  grains  average  from  .05  to  .20  mm.  in  diam- 
eter, though  varying  from  .01  to  I  mm.  The  grains  are 
rounded  to  oval  in  shape  and  in  some  cases  give  suggestions 
of  crystal  boundaries.  They  are  white  as  isolated  but 
colorless  in  thin  section.  They  contain  few  inclusions  or 
cracks.  Their  determination  as  forsterite  rests  on  the 
following  analysis  by  Fahrenhorst.f 

SiO2     FeO     CaO     MgO 

43.29    0.52      1.13      54.92          =99.86 

SiO2  :  FeO+CaO+MgO=i  :  1.95.     6  =  3.2 

A  nearly  pure  magnesium  silicate  is  thus  indicated.  The 
grains  were  separated  for  the  analysis  by  dissolving  the  iron 
in  copper  ammonium  chloride. 

CHRYSOLITE 

This  mineral  is,  next  to  nickel-iron,  the  most  abundant 
constituent  of  meteorites.  It  is  an  essential  ingredient  of 
the  pallasites,  mesosiderites,  grahamites,  and  amphoterites, 
and  of  one  meteorite,  Chassigny,  it  is  practically  the  only 
constituent.  In  all  the  chondritic  meteorites  chrysolite  plays 
a  large  role  and  is  probably  the  most  abundant  constituent 
since  an  average  of  66  analyses  compiled  by  Rammels- 

*Pogg.  Ann.,  1825,  4,  174-180. 
fTsch.  Min.  Mitth.,  1906,  25,  181. 
tMeteoritenkunde,  Heft  II,  275. 


182 


METEORITES 


berg  showed  the  proportion  of  soluble  to  insoluble  silicates 
or  essentially  of  chrysolite  to  bronzite  to  be  9  :  8.*  The 
presence  of  chrysolite  in  meteorites  was  early  recognized. 

Pallas  in  1776  de- 
scrrbed  the  Pallas 
iron  as  containing 
"  rounded  and  elong- 
ated drops  of  a  very 
brittle  but  hard, 
amber-yellow, 
transparent  glass. " 
Count  Bournon  in 
1802  showed  that 
this  was  similar  to 
terrestrial  chrysolite 
and  Howard  in  the 
same  year  gave  an 
analysis  which  was 
doubtless  incorrect 
in  the  percentage  of 
silica  shown  (55.7 
per  cent)  but  other- 
wise indicated  the 
mineral  to  be 
chrysolite. 

The  chrysolite  of 
meteorites  occurs  in 
the  form  of  crystals, 
grains,  and  frag- 
ments. As  crystals 
it  has  been  described 
fully  only  fiom  the 
Pallas  and  Lodran 


FIG.  56. —  Forms  of  chrysolite  from  the  Pallas 
meteorite.  Upper  figure,  natural  form  of 
crystal.  Lower  figure,  as  ideal  crystal  would 
appear.  After  Kokscharow. 


meteorites.  In  these  it  occurs  in  rounded  forms  with  facets 
separated  by  rounded  surfaces  as  shown  in  Fig.  56.  The 
lower  figure  shows  the  crystal  form  which  would  be  pro- 
duced if  the  planes  were  continued.  Rose  in  1825  deter- 
mined ii  forms  and  Kokscharow  in  1870  added  8  to  these. 

*Chem.  Natur.  der  Met.,  1879,  ii,  47-51. 


COMPOSITION   OF   METEORITES 


183 


The  following  19  forms  have  thus  far  been  identified, 
letters  are  those  of  Kokscharow. 


The 


p.  . 

.  .001 

w 

.  .012 

V  .  . 

.  102 

e.  .  .  in 

T  . 

.  .010 

h. 

.  .Oil 

7  • 

.hol 

f.  .  .  121 

n  .  . 

.  .  no 

k. 

.  .021 

d. 

.  IOI 

/.  .  .  131 

s  .  . 

.  .  120 

i  . 

.  .041 

q- 

.116 

fl...hkl 

r  .  . 

.  130 

0 

..  106 

0  .  . 

.112 

Fig.  57  shows  simple  forms  observed  by  Rose. 

The  rounded  appearance  of  the  chrysolite  crystals  so 
characteristic  of  its  occur- 
rence in  the  pallasites  seems 
to  be  peculiar  to  meteorites 
as  it  has  never  been  ob- 
served terrestrially.  It 
suggests  partial  fusion.  In 
certain  of  the  iron-stone 
meteorites,  notably  Eagle 
Station,  the  chrysolite  is  in 
angular  instead  of  rounded 
forms.  In  this  meteorite 
the  grains  reach  a  dimension 


FIG.  57. —  Common   forms  of  meteoritic 
chrysolite.     After  Rose. 


of  35  mm.  while  in  the  meteorite  of  Mincy,  Kunz*  reported 
a  crystal  measuring  10  by  8  centimeters  (4  by  3  inches). 

In  color  the  chrysolite  of  meteorites  varies  from  yellowish- 
green  to  yellowish-white  and  from  transparent  to  opaque. 
It  also  frequently  appears  dark  reddish-brown  and  opaque 
owing  to  staining  by  iron  oxide.  In  the  chondritic  meteor- 
ites chrysolite  may  constitute  most  of  the  chondri  and  also 
occur  as  an  important  constituent  of  the  ground  mass.  In 
the  chondri  of  which  it  forms  the  principal  part  it  is  usually 
more  or  less  intergrown  with  glass,  while  in  other  chondri  it 
may  be  accompanied  by  pyroxenes,  nickel-iron,  etc.  In 
chondri  made  up  of  chrysolite  and  glass  alternate  arrange- 
ments of  the  two  substances  are  common  and  a  more  or  less 
regular  pattern  is  usual.  Thus  the  lamellae  rriay  run  in  a 
single  direction,  in  two  directions  or  four  directions  (Fig. 
58),  or  the  pattern  may  be  fan-shaped,  mesenteric,  or  net- 

*Am.  Jour.  Sci.,  1887,  3,  34,  467. 


184 


METEORITES 


like.  In  all  these  cases  there  may  be  simultaneous  extinc- 
tion of  the  chrysolite  lamellae  in  polarized  light,  or  circular 
extinction,  or  different  extinction  in  different  directions. 
Tschermak  applied  the  term  monosomatic  to  those  chondri 
which  he  regarded  as  consisting  of  one  individual  and  poly- 
somatic  to  those  consisting  of  several  individuals,  but  it  is 
difficult  in  many  if  not  most  cases  to  determine  whether  one 
or  many  individuals  are  present.  Often  the  nucleus  or  cen- 
tral portion  of  a  chondrus  will  be  of  one  generation  and  the 
rim  of  another.  At  least  a  well-marked  gap  often  sepa- 
rates the  two.  Instead  of  occurring  in  lamellar  form  in  the 


FIG.  58. —  Typical  arrangements  of  chrysolite  lamellae  in  chondri. 

chondri  chrysolite  may  appear  as  porphyritic  crystals.  These 
often  have  well-defined  crystal  outlines  among  which  the 
forms  of  the  prism  and  brachypinacoid  predominate.  Again 
the  chrysolite  chondri  may  be  made  up  of  grains  of  differ- 
ent size.  It  is  not  uncommon  to  observe  a  ring  of  nickel- 
iron  and  pyrrhotite  bordering  the  chrysolitic  chondri.  In 
Chassigny,  made  up  almost  wholly  of  chrysolite,  the  min- 
eral is  in  the  form  of  greenish-yellow  grains,  small  and  con- 
siderably fissured.  It  also  contains  inclusions  of  brownish 
glass  to  some  extent.  The  chrysolite  of  Angra  dos  Reis 
contains  negative  crystals  reaching  a  size  of  .02  mm.  on 
which  the  forms  oio,  no,  021,  and  101  were  recognized  by 
Tschermak.  He  also  noted  rounded  inclusions  of  brownish 
glass  and  canals  filled  with  a  yellowish-brown  amorphous 
substance.  In  Zavid,  Berwerth  observed  crystals  made  up 
of  rounded  grains  oriented  alike  optically.  These  crystals 
were  fresh  in  the  interior  but  toward  the  exterior  showed 
low  interference  colors  which  seemed  to  indicate  a  molecu- 
lar change.  These  forms  were  regarded  by  Berwerth*  as 

*Wiss.  Mitth.  Bosni.  u.  Herzegov.,  1901,  8,  412-413. 


COMPOSITION   OF   METEORITES  185 

having  constituted  one  individual  which  was  later  separated. 
In  contrast  to  this  Tschermak*  found  that  large  porphyritic 
chrysolites  in  Goalpara  were  made  up  of  numerous  small 
grains  of  different  orientation  showing  that  the  individuals 
had  been  formed  by  aggregation.  The  chrysolite  of  the 
mesosiderites  and  grahamites  is  usually  in  the  form  of  in- 
dividuals of  large  size.  These  individuals  have  crystal 
boundaries  but  are  rarely,  if  ever,  suitable  for  measurement. 
Opaque  inclusions  consisting  probably  chiefly  of  pyrrhotite 
and  dark  glass  are  common.  Often  the  exterior  of  the  in- 
dividuals is  of  a  two-fold  nature.  The  outer  zone  is  fine 
grained  and  turbid,  the  inner  impregnated  with  black  grains. 
The  interior  often  contains  fine,  needle-like  inclusions  of 
gray  or  brown  color,  arranged  parallel  to  two  directions  and 
showing  a  fine  grating  structure. 

It  is  in  the  pallasites  that  chrysolite  shows  its  most  com- 
plete development.  Here  it  occurs  in  rounded  or  angular 
forms  on  which  crystal  planes  can  often  be  observed.  The 
individuals  are  usually  of  moderate  size,  at  least  not  as 
large  as  in  the  mesosiderites  and  grahamites.  The  chrysolite 
of  the  pallasites  seems  to  have  formed  before  the  nickel- 
iron,  for  when  the  facetted  or  rounded  individuals  of 
chrysolite  are  removed  from  the  nickel-iron,  the  latter 
cavities  conform  to  the  shape  of  the  chrysolite.  A  promi- 
nent feature  of  the  pallasite  chrysolites  is  the  abundance 
of  fissures  which  traverse  them.  These  are  irregular  in 
their  course  and  dimensions  and  are  not  cleavage  planes. 
Characteristic  of  the  fissures  is  the  deposit  of  an  opaque, 
reddish-brown  coating  of  iron  oxide  along  their  walls. 
Abundant  inclusions  also  characterize  the  chrysolite  of  some 
pallasites.  Some  of  these  inclusions  are  rod-like  and  hair- 
like  forms  usually  lying  parallel  and  sometimes  in  three  di- 
rections. Other  inclusions  are  in  the  form  of  opaque,  dark 
grains  often  with  a  dendritic  arrangement.  At  rare  inter- 
vals gas  cavities  and  hollow  canals  may  be  observed.  The 
distribution  of  the  chrysolite  in  the  nickeliron  is  usually 
fairly  uniform  and  regular  but  it  may  be  irregular.  Some 
individuals  of  the  Brenham  fall  show  abundant  chrysolite, 

*Sitzb.  Wien  Akad.,  1870,  62,  2,  856. 


186  METEORITES 

others  none  at  all.  The  color  of  the  chrysolite  of  the  pal- 
lasites  varies  also.  In  some,  as  Brenham,  it  is  transparent, 
yellowish-green  and  of  resinous  luster;  in  others  it  is  dark, 
opaque,  and  dull. 

Cohen*  remarks  as  especially  characteristic  of  meteoritic 
chrysolite  the  following:  "Abundance  of  fissuring,  tendency 
to  incomplete  growths,  richness  in  inclusions,  and  lack  of 
microlites,  fluid  inclusions,  and  alteration  products." 

ANALYSES  OF  METEORITIC  CHRYSOLITE 

SiO2  MgO  FeO  MnO  A12O3  Total 

1  42.02  47 .25  12.08  tr.  0.46  101.81 

2  40.96  46-43  12. 61  ....  100. 

3  40.87  46.93  12. ii  ....  ....  99.91 

4  40.86  47.35  11.72  0.43  100.36 

5  40.83  47.74  11.53  0.29  100.39 

6  40.79  47-05  12.10  0.02  99.96 

7  40.70  48.02  10.79  0.14  tr-  99 -65 

8  40.26  47-26  11.86  ....  ....  99.38 

9  40.24  47-41  11.80  0.29  0.06  99.80 

10  40.02  45-6o  14.06  o.io  99.78 

11  39-94  47-02  12.93  o.i i  lob. 

12  39-So  43-68  16.34      tr-  o  37  100.19 

13  39-6i  48.29  11.88  0.19  0.21  100.18 

14  39-H  4763  13.18  ....  ....  99.95 

15  38.48  48.42  11.19  0-31  0.18  98.58 

16  38.25  49.68  11.75  °-10  99  78 

17  37-90  41.65  19 . 66 0.42  99-63 

18  37-58  43-32  18.85  99-75 

19  37-34  33-6o  27.88  0.48  {o.Vo}          I0°- 

20  36.92  43.16  15.49  i  68  97.25 

21  35-33  33-35  31-32  100. 

Specific  gravities  of  the  above  vary  from  3.35-3.42. 
Ratios  of  SiO2  :  MgO  +  (Fe,  Mn)O  =  i  :  1.928 — 2.209  and 
of  MgO  :  (Fe,  Mn)O=7.9 — 1.9.  :  i 

REFERENCES 

1.  Mincy.     Smith:   Am.  Jour.  Sci.,  1865,  3,  40,  215. 

2.  Lodran.     Tschermak:   Sitzb.  Wien  Akad.,  1870,  61,  ii,  467-469. 

3.  Medwedewa.     Baumhauer:    Arch.  Neerland.   des  Sciences,   1871,  6,    167. 
Ni  and  Mn  in  traces. 

4.  Medwedewa.     Berzelius:    Pogg.  Ann.,  1834,  33,  134.     0.17  SnO2.      Traces 
of  K20,  Na20. 

5.  Medwedewa.     Walmstedt:    Kongliga  Vetenskaps  Academiens  Handlingar, 
Stockholm,  1824,  364.     Traces  CaO  and  Al2O.-i. 

6.  Imilac.     Kobell:   Korrblatt  des  zool.  min.  Ver.  in  Regensburg,  1851,  v,  No. 
7,  112.     Ni,  Co,  Mn,  As,  looked  for  but  not  found. 

*Meteoritenkunde,   Heft   I,   262. 


COMPOSITION   OF   METEORITES  187 

7.  Brenham.     Eakins:    Am.  Jour.  Sci.,  1890,  3,  40,  315.     Center  of  crystals. 
.02  per  cent  NiO,  .18  per  cent  Fe2O3. 

8.  Marjalahti.     Borgstrom.     Die    Met.    Hvittis    u.    Marjalahti,    Helsingfors, 
1903,  63.     In  addition  0.12  per  cent  Cr2Os,  0.21  per  cent  Na2O,  and  0.05  per  cent 
K2O  were  found. 

9.  Medwedewa.     Herzog  von  Leuchtenberg.     M.  Acad.  Imp.  Pet.,  1870,  15, 
No.  6,  40.     Mean  of  3  analyses.     .08  per  cent  SnO2. 

10.  Anderson.     Kinnicut:   Am.  Jour.  Sci.,  1887,  3,  33,  231. 

11.  Brenham.     Eakins:   Am.  Jour.  Sci.,  1890,  3,  40,  315.     Dark  outer  portion. 
Calculated  to  100  after  deducting  14.81  per  cent  troilite. 

12.  Pawlodar.     Antipoff:      Chemischer    Centralblatt,     1899,    i,    802.    Trace 
Sn02 

13.  Rokicky.     Inostranzeff:  Verhandl.  russ.  kais.  min.  Gesellschaft,  St.  Peters- 
burg, 1869,  2,  4,  311. 

14.  Admire,     Merrill:    Proc.  U.  S.  Nat.  Mus.,  1902,  24,  910.     Material  fresh 
and  free  from  inclusions. 

15.  Medwedewa.     Stromeyer:   Nachrichten  k.  Gesell.  d.  Wiss.  zu  Gortingen, 
1824,  2079.     Mean  of  3  analyses.     Nickel  looked  for  but  not  found. 

16.  Medwedewa.     Stromeyer:   Nachrichten  k.  Gesell.  d.  Wiss.  zu  Cottingen, 
1824,  2079. 

17.  Eagle  Station.    'Mackintosh:    Am.  Jour.  Sci.,  1887,  3,  33,  232. 

18.  Rokicky.     Rammelsberg:    Monatsber.  Berlin  Akad.,  1870,  445. 

19.  Chassigny.     Damour:     Comptes    Rendus,    1862,    55,    593.     An    insoluble 
residue  of  3.77  per  cent  was  deducted  and  an  amount  of  chromite  calculated  from 
0.75  per  cent  Cr2Os. 

20.  Imilac.     Schmid:   Pogg.  Ann.,  1851,  84,  503. 

21.  Chassigny.     Vauquelin:   Ann.  Chim.  et  Phys.,  1816,  i,  53.     After  deduct- 
ing chromite  reckoned  from  2  per  cent  Cr2Os. 

A  marked  feature  of  the  composition  of  meteoritic  chryso- 
lite is  the  almost  complete  absence  of  nickel  oxide,  whereas 
in  terrestrial  chrysolite  it  is  an  almost  constant  constituent. 
The  difference  is  doubtless  due,  as  Daubree  has  suggested,, 
to  incomplete  oxidation.  Iron  is  more  easily  oxidized  than 
nickel  and  nickel  would,  therefore,  not  be  attacked  by 
oxygen  until  complete  oxidation  of  the  iron  had  taken 
place.  As  the  presence  of  nickel-iron  in  meteorites  shows 
that  such  complete  oxidation  almost  never  takes  place,  the 
presence  of  nickel  in  such  products  of  oxidation  as  chrysolite 
is  hardly  to  be  expected. 

APATITE 

Apatite  was  described  by  Berwerth*  as  occurring  in  the 
meteorite  of  Kodaikanal.  Short-prismatic,  skeletal,  and 
granular  forms  were  noted,  the  skeletal  forms  being  horse- 
shoe and  knob-shaped.  Cross  sections  showed  prismatic 
cleavage.  The  mineral  was  colorless  and  transparent.  For 

*Tsch.  Min.  u.  Pet.  Mitth.,  1906,  25,  188. 


188  METEORITES 

the  most  part  it  was  intergrown  with  pyroxene  and  wein- 
bergerite,  from  which  it  was  distinguished  by  its  optical 
characters.  The  intergrowths  also  gave  a  reaction  for 
phosphoric  acid.  Small,  colorless  grains  which  were  opti- 
cally negative  and  uniaxial,  and  showed  a  double  refraction 
weaker  than  that  of  nepheline,  were  found  by  Ludwig  and 
Tschermak*  in  Angra  dos  Reis  and  referred  by  them  to 
apatite.  A  content  of  0.13  per  cent  P2O5  shown  by  analysis 
seemed  further  to  indicate  this  mineral. 

A  colorless  constituent  with  irregular  outlines  found  in 
many  chondritic  meteorites  by  Tschermak  and  referred  by 
him  doubtfully  to  monticellite  is,  according  to  later  investi- 
gations by  Merrill,!  probably  the  phosphate  of  lime,  fran- 
colite.  The  mineral  as  seen  in  meteorites  is  weakly  bire- 
fracting  with  interference  colors  not  exceeding  gray-white 
of  the  first  order.  It  is  biaxial  and  probably  positive,  in 
which  latter  respect  it  differs  from  francolite.  It  is  easily 
and  completely  soluble  in  nitric  acid. 

HYDROCARBONS 

The  hydrocarbons  found  in  meteorites  may  be  divided, 
following  Cohen, {  into  three  classes:  (a)  compounds  of  car- 
bon and  hydrogen;  (b)  compounds  of  carbon,  hydrogen,  and 
sulphur;  and  (r)  compounds  of  carbon,  hydrogen,  and  oxygen. 
Hydrocarbons  especially  characterize  the  carbonaceous 
meteorites  but  have  been  obtained  from  some  other  meteor- 
ites, such  as  Collescipoli  and  Goalpara.  The  hydrocarbons 
of  the  first  class  are  obtained  by  treating  carbonaceous 
meteorites  with  alcohol  or  ether.  These  hydrocarbons  are 
resinous  or  wax-like  bodies  which  completely  volatilize  on 
the  application  of  heat.  When  heated  in  a  closed  tube  the 
resinous  substances  first  fuse,  and  then  are  decomposed 
forming  amorphous  carbon  and  an  oil  having  a  bituminous 
or  fatty  odor.  Such  substances  were  considered  by  Wohler 
similar  to  ozocerite  and  by  Shepard  they  were  regarded  as 
meteoritic  petroleum.  Friedheim  states  that  a  substance 

*Tsch.  Min.  u.  Pet.  Mitth,  1909,  28,  112. 
fProc.  Nat.  Acad.  Sci.,  1915,  I,  302. 
JMeteoritenkunde,  Heft.  I,  p.  159. 


COMPOSITION   OF   METEORITES  189 

extracted  by  him  from  the  meteorite  of  Nagaya  by  means 
of  ether  had  a  bituminous  odor,  volatilized  at  200°  and  re- 
sembled a  product  of  distillation  of  brown  coal.  A  similar 
substance  extracted  by  Roscoe  from  the  meteorite  of  Alais 
was  found  to  have  a  composition  corresponding  nearly  to 
the  formula  CH2n. 

Hydrocarbons  of  the  second  class  were  obtained  by  Smith 
by  treating  the  graphite  of  iron  meteorites  and  some  car- 
bonaceous meteorites  with  ether.  The  compounds  obtained 
were  fusible  and  volatile.  He  regarded  them  as  having  the 
general  composition  C4Hi2S5.  He  obtained  similar  products 
by  treating  cast  iron  with  ether  or  petroleum  as  did  also 
Berthelot  by  the  action  of  ether  on  sulphur  or  iron  sulphide 
in  the  presence  of  oxygen. 

Hydrocarbons  of  the  third  class  have  been  obtained  from 
the  meteorites  of  Orgueil  and  Hessle.  The  Orgueil  extract 
resembled  peat,  humus,  or  lignite  in  its  composition  and 
properties.  That  from  Hessle  had  approximately  the  com- 
position TlCgHgOa. 

The  above  mentioned  facts  make  it  clear  that  a  number 
of  meteorites  contain  products  of  an  easily  destructible, 
volatile,  and  combustible  character  which  resemble  ter- 
restrial bitumens,  petroleum,  or  oxygenated  hydrocarbons. 
The  quantity  of  these  products  is  relatively  small,  being 
less  than  I  per  cent  in  the  majority  of  meteorites  in  which 
they  occur.  Yet  that  they  occur  at  all  is  significant.  While 
some  have  urged  that  these  products  might  have  arisen  from 
the  union  of  their  elements  in  the  terrestrial  atmosphere 
there  seems  little  reason  for  doubting  their  pre-terrestrial 
origin.  There  is  no  evidence  that  life  had  anything  to  do 
with  their  origin.  We  must  conclude  that  they  were  formed 
in  an  inorganic  way  by  a  union  of  their  elements. 

The  occurrence  of  hydrocarbons  in  meteorites  shows  (i) 
that  such  meteorites  could  not  have  been  subjected  to  any 
high  degree  of  heat,  at  least  subsequent  to  the  formation  of 
these  compounds,  and  (2)  that  the  heating  of  meteorites 
during  their  fall  to  the  earth  must  have  been  in  many  cases 
only  superficial. 

The  trails  of  light,  sometimes  enduring  several  minutes, 


190  METEORITES 

which  have  been  observed  following  in  the  wake  of  some 
meteors  may  perhaps  indicate  the  presence  of  carbonaceous 
matter  in  those  bodies.  The  fall  of  Hessle  was  accompanied 
by  luminous  effects  and  the  precipitation  of  a  brownish-black 
powder  which  contained  71  per  cent  carbonaceous  matter. 
Some  carbonaceous  meteorites  have  fallen,  however,  without 
exhibiting  any  marked  luminous  phenomena. 

GLASS 

This  is  an  abundant  constituent  of  the  stone  meteorites, 
few  if  any  being  entirely  without  it.  It  is  variously  dis- 
tributed, occurring  now  as  vein  matter,  now  scattered 
through  the  substance  of  chondri,  now  enclosed  in  the  sub- 
stance of  a  single  mineral,  and  now  enclosing  various  min- 
erals. 

In  Parnallee,  Mezo-Madaras,  Chassigny,  Farmington,  and 
a  few  other  meteorites  glass  was  so  abundant  as  to  have 
been  described  as  forming  a  network  in  which  other  minerals 
are  imbedded.  Its  occurrence  in  this  manner  is  rare,  how- 
ever, it  playing  usually  a  merely  accessory  part.  It  chiefly 
abounds  as  inclusions  and  intergrowths  in  chrysolite,  taking 
in  this  association  a  great  variety  of  forms.  Other  minerals 
too,  frequently  have  inclusions  of  glass.  It  may  occur  in 
fragments  of  considerable  size  or  the  particles  may  be  of  a 
dustlike  minuteness.  The  prevailing  color  of  the  glass  of 
meteorites  is  brown.  Much  is,  however,  colorless  and  some 
occurs  so  dark  as  to  be  opaque.  Grayish  and  greenish  tones 
occur  but  are  rare. 

In  chondri  glass  is  notably  abundant.  By  all  these  occur- 
rences a  rapid  crystallization  or  cooling  of  the  meteorite 
substance  is  indicated.  Like  the  glass  of  terrestrial  lavas 
it  seems  to  be  the  result  of  cooling  so  rapidly  as  to  prevent 
differentiation  and  orderly  crystallization. 

INCLUDED  GASES 

That  meteorites  might  contain  an  appreciable  quantity 
of  free  gases  in  addition  to  their  solid  constituents  was 
probably  early  surmised  but  the  first  investigation  of  the 


COMPOSITION   OF   METEORITES 


191 


matter  seems  to  have  been  made  by  Graham.*  In  1867 
this  investigator  heated  a  strip  of  Lenarto  to  red  heat  in  a 
vacuum  for  35  minutes.  From  5.78  cc.  of  the  meteorite 
he  thus  obtained  5.38  cc.  of  gas  or  0.93  volumes.  The 
nature  of  this  gas  he  did  not  investigate  but  on  further 
heating  the  iron  for  100  minutes  he  obtained  1.65  volumes 
of  gas  which  had  the  composition:  H2,  85.68;  CO,  4.46;  CO2 
none;  N2,  9.86.  As  he  thus  obtained  gas  to  about  three 
times  the  volume  of  the  specimen,  and  this  gas  was  largely 
hydrogen,  Graham  concluded  that  the  meteorite  must 
have  come  from  a  dense  atmosphere  of  hydrogen  gas.  In 
1872  Malletf  subjected  a  piece  of  Staunton  weighing  124+ 
grams,  to  a  treatment  like  that  given  by  Graham  to  Lenarto 
and  obtained  after  a  total  heating  of  14^  hours,  3.17 
volumes  of  gas  having  the  composition:  H2, 35. 83;  CO,  38.33; 
CO2,  9.75;  N2,  16.09. 

Mallet's  results  differed  from  those  of  Graham  in  finding 
less  H2  and  more  CO  and  CO2.  Subsequent  to  the  work  of 
Graham  and  Mallet  elaborate  investigations  of  the  gases 
of  meteorites  were  made  by  A.  W.  WrightJ  which  form  the 
foundation  of  most  of  our  knowledge  of  these  substances. 
Wright  investigated  the  gases  given  off  from  six  stone  and 
five  iron  meteorites  and  obtained  the  following  results,  the 
numbers  in  the  third  line  in  each  case  giving  the  percent- 
age of  each  gas  in  the  total  amount  obtained.  They  are 
not  the  simple  averages  of  the  numbers  above  them  but  the 
means  reduced  according  to  the  volumes  in  each  case: 

ANALYSES  OF  GASES  OF  STONE  METEORITES 


Name 

Tempera- 
ture 

Volumes 

H2 

C02 

CO 

N2 

CH4 

New  Concord 

500° 
Red  heat 

2.06 
0-93 

12.37 
69-43 

82.28 
16.79 

2.16 

8.71 

0-93 
3  4i 

2.26 
1.66 

Total 

2  99 

31-89 

59.88 

4.40 

1.78 

2.05 

176. 


*Proc.  Roy.  Soc.,  1867,  15,  502. 
fProc.  Roy.  Soc.,  1872,  20,  365-370. 

.  Jour.  Sci.,  1875,  3,  9,  294-302  and  459~46°;  ^76,  3,  n,  253-262;  12,  165- 


192  METEORITES 

ANALYSES  OF  GASES  OF  STONE  METEORITES— Continued 


Name 

Tempera- 
ture 

Volumes 

H2 

C02 

CO 

N2 

CH4 

Homestead 

500° 
Red  heat 

1.04 
1.46 

34.82 
74-49 

58.04 

19.16 

4.01 

O.2I 

3-i3 
6.14 

0.0 
0.0 

Total 

2.50 

57-88 

35-44 

I.  80 

4.88 

0.0 

Pultusk 

350° 
Red  heat 

0.99 
0.76 

13  36 
49  99 

81.01 
33-97 

1.99 

7-35 

1.91 
2.69 

\n 

6.00 

Total 

i-75 

29.50 

60.29 

4-35 

2.25 

3  61 

Parnallee 

350° 
Red  heat 

1.56 
1.17 

8.72 
20.03 

87-53 
72-43 

1-13 

2-53 

i  .40 
1.79 

I  .  22 
3-22 

Total 

2-73 

13-59 

81.02 

i  74 

i-57 

2.08 

Weston 

350° 
Red  heat 

2.69 
0.80 

8-59 
28.16 

86.29 
62.18 

1.84 
3-43 

2.09 
3-13 

I.I9 
3.10 

Total 

3-49 

13.06 

80.78 

2.20 

2-33 

1.63 

Cold 
Bokkeveld 

300° 
500° 

7-45 
17.78 

Tr. 

0-54? 

87-34 
95-53 

5.08 
1.32 

1.65 
0.47 

5-93 
2.14 

Total 

25-23 

0.38? 

93-" 

2.42 

0.84 

3-25 

ANALYSES  OF  GASES  OF  IRON  METEORITES 


Name 

Tempera- 
ture 

Volumes 

H2 

C02 

CO 

N2 

Tazewell 

500° 
Red  heat 

1.87 
1.30 

4i-5i 
44.76 

18.34 
7.76 

38.45 

45-75 

1.70 
i-73 

Total 

3-17 

42.66 

14.40 

41-23 

1.71 

Shingle 
Springs 

500° 
Red  heat 

0.65 
0.32 

60.92 
84.40 

19.98 

I  .10 

13-52 
10.39 

5-58 
4  ii 

Total 

0.97 

68.81 

13  64 

12.47 

5.08 

Magura 

500° 
Red  heat 

8.89 
38.24 

40.62 
12.84 

18.20 

11.25 

38.72 
74-59 

2.46 
1.32 

Total 

47-13 

18.19 

12.56 

67.71 

i  54 

Red 
River 

500° 
Red  heat 

I  .  10 
O    IQ 

81.81 

4.Q    24. 

9.76 

2  18 

8.43 
48  58 



Total 

I    2Q 

76    70 

8  so 

14.   62 

Charlotte 

Total 

2.20 

71.40 

I3-30 

I5-30 

COMPOSITION  OF   METEORITES 


193 


The  most  noticeable  feature  of  these  analyses  is  the  con- 
trast which  is  shown  between  the  stone  and  iron  meteorites 
in  the  kind  of  gases  evolved.  In  the  stone  meteorites  CO2  is 
more  abundant,  in  the  iron  meteorites  H  and  CO. 

Several  other  experiments  made  by  Wright  served  to 
answer  special  inquiries,  such  as  whether  the  different 
ingredients  of  a  stone  meteorite  varied  as  to  the  kinds  of 
gas  evolved,  what  the  effects  of  different  temperatures  were, 
and  what  the  effects  of  time. 

The  test  of  the  different  portions  of  a  stone  meteorite 
gave  the  following: 


Volumes 

H2 

C0+C02 

N« 

I  .00 

1.90 

2.08 

Entire  stone  
Magnetic  portion,  0.51  
Non-magnetic  portion,  0.97  

1.87 
}..* 

50.93 
59-38 
30.96 

48.07 
•  38.72 
66.96 

The  results  show  that  the  distribution  of  gases  among 
the  different  ingredients  of  a  stone  meteorite  is  about  that 
between  stone  and  iron  meteorites. 

The  effects  of  different  temperatures  on  a  specimen  of 
Homestead  were  as  follows: 


Gas 

C(V 
CO. 
H,.. 

N2.. 


.00 

4  54 


Total 


100. 


250 

93-32 
1.82 

5-86 
o.oo 

IOO. 


Below 

Low 

Full 

red  heat 

red  heat 

red  heat 

42.27 

35-82 

5.56 

5  ii 

0.49 

0.00 

48.06 

58.51 

87.53 

4  56 

5.18 

6.91 

IOO. 


Here  it  will  be  seen  that  a  striking  decrease  in  CO2  and 
increase  in  H  occurs  with  rising  temperature. 

In  order  to  determine  the  effect  of  time,  if  any,  Wright 
analyzed  the  gases  from  a  Homestead  specimen  three 
months  after  its  fall  and  a  year  later.  The  gases  given  off 
were  similar  in  both  cases  except  that  a  slight  loss  of  CO2 
occurred. 

Following  Wright  several  determinations  of  meteoritic 
gases  have  been  made  of  which  the  following  are  the  most 
important.  Flight*  determined  the  gases  from  two  iron 
meteorites,  Rowton  and  Cranbourne,  as  follows: 

*Phil.  Trans.,  1882,  No.  171,  893-6. 


194  METEORITES 

Name Vol.  H2  CO2  CO  N2  CH4 

Cranbourne 3-59         45-79         0.12         31.88          17.66         4.55 

Rowton 6.38         77  78         5.15  7-34  9  72         •••• 

These  results  correspond  with  those  of  previous  in- 
vestigators. 

Several  stone  meteorites  were  tested  for  gases  by  Dewar 
and  Ansdell*  in  1886.  Their  results,  which  follow,  harmo- 
nize with  those  of  Wright. 

Name Vol.            H2  CO2  CO  N2  CH4 

Pultusk 3.54  18.14  66.12  5.40  2.69  7.65 

Mocs 1.94  22.94  64.50  3.90  3.67  441 

Dhurmsala .  .  .- 2.51  28.48  63.15  1.31  1.31  3.90 

The  values  for  Pultusk  were  obtained  from  a  completely 
encrusted  stone  in  order  to  minimize  the  effect  of  possible 
absorption  of  gases  from  the  atmosphere.  For  the  other 
meteorites  coarse  powder  was  used.  The  results  do  not 
indicate  that  atmospheric  absorption  influences  the  gases 
evolved.  In  the  same  investigation  Dewar  and  Ansdell 
analyzed  the  gases  from  Orgueil,  a  carbonaceous  meteorite, 
with  unusual  results,  since  57.87  volumes  were  given  off  of 
which  SO2  constituted  83  per  cent.  The  investigators 
regarded  the  SO2  as  arising  from  the  decomposition  of  sul- 
phate of  iron.  Omitting  this,  9.8  volumes  remained  which 
had  the  following  composition:  CO2,  76.05;  CO,  11.67; 
CH4,  8.93;  N2,  3-33-  This  result  is  remarkable  for  the 
absence  of  hydrogen,  as  it  was  evolved  by  all  other  meteorites, 
but  it  may  have  been  given  ofF  and  combined  with  some 
other  ingredient. 

In  an  effort  to  discover  what  portion  of  a  meteorite,  if 
any,  might  be  the  parent  of  the  gases  evolved,  the  same  in- 
vestigators analyzed  a  number  of  graphites,  including  that 
of  meteorites  (termed  celestial  graphite  by  them)  for  their 
gaseous  contents.  Considerable  quantities  of  gases  were 
obtained  from  these  graphites,  but  Dewar  concluded  that 
"the  large  quantities  of  gas  occluded  in  celestial  meteorites 
cannot  be  explained  by  any  special  absorptive  power  of  this 
variety  of  carbon." 

Subsequent  to  the  work  of  Dewar  and  Ansdell  little  was 
done  by  any  investigator  in  the  study  of  meteorite  gases 

*Proc.  Roy.  Inst.,  11,  541-552. 


COMPOSITION   OF   METEORITES  195 

until  in  1908  R.  T.  Chamberlin*  reviewed  the  whole  subject 
and  determined  the  gases  from  two  stone  and  one  iron 
meteorite.  His  determinations  from  meteorites  which  had 
not  previously  been  tested  were  as  follows: 

Name Vol.  H2  CO,           CO  N2  CH4 

Allegan 0.49  16.73  41-74  38-6i  o.oo  2.92 

Estacado 0.84  36.25  28.47  29.31  1.69  3.39 

Toluca  — 

(a] 24.42  17.84  43.29  35.48  1.93  1.44 

(b) 10.09  18.49  22.32  53.99  3.19  1.91 

(c) 1.85  14.54  6.40  71.05  5.53  2.35 

The  three  determinations  of  Toluca  were  made  in  an  ef- 
fort to  obtain  material  free  from  rust.  For  (a)  borings  and 
filings  which  proved  to  be  slightly  rusted  were  used,  for  (b) 
borings  which  were  found  to  contain  a  little  rust,  and  for  (c) 
borings  free  from  rust.  Chamberlin  regarded  the  results 
of  these  three  determinations  as  showing  that  the  presence 
of  a  little  rust  had  a  great  effect  on  the  gases  produced.  He 
suggested  that  the  great  volume  of  gas  obtained  by  Wright 
from  Magura  (47.13  vols.)  was  probably  due  to  the  presence 
of  rust. 

Chamberlin's  results  differ  somewhat  from  those  of 
.previous  investigators  in  showing  less  contrast  in  the  gases 
evolved  by  stone  as  compared  with  iron  meteorites  and 
in  showing  more  CO.  Still  the  differences  from  previous 
results  are  not  great,  and  on  the  whole  support  earlier  con- 
clusions as  to  the  nature  of  the  gases  evolved  from  stone  and 
iron  meteorites  respectively. 

To  recapitulate,  and  omitting  the  results  of  Magura  and 
Orgueil  and  two  of  Toluca  as  being  affected  by  variables, 
the  gases  obtained  from  stone  and  iron  meteorites  are  as 
follows,  the  arrangement  being  in  accordance  with  the  per- 
centage of  hydrogen: 

SUMMARY  OF  ANALYSES  OF  GASES  FROM  STONE  METEORITES 

Name  Vols.      H       CO2      CO  N      CH4   Analyst 

Homestead.., 2.5057.8835.44     1.80  4.88  o.oo  Wright 

Estacado o .  84  36 . 25  28 . 47  29 . 3 1  1 . 69  3  . 39  Chamberlin 

New  Concord 2.99  31 .89  59.88     4.40  1.78  2.05  Wright 

Pultusk 1.75  29.5060.29     4.35  2.25  3.61  Wright 

Dhurmsala 2. 51   28. 48  63. 15     1.31  1.31   3  .90  Dewar  and  Ansdell 

Mocs 1.9422.9464.50     3.90  3.674.41  Dewar  and  Ansdell 

*Pubs.  Carnegie  Inst.  of  Washington,  1908,  No.  106. 


196  METEORITES 

SUMMARY  OF  ANALYSES  OF  GASES  FROM  STONE 

METEORITES— Continued 
Name  Vols.      H       CO2      CO         N      CH4   Analyst 

Pultusk 3.5418.1466.12     5.40     2.697.65   Dewar  and  Ansdell 

Allegan 0.49  16.73  41.74  38.61     o.oo  2.92  Chamberlin 

Parnallee 2.63   13.5981.02     1.74     1 .57  2.08  Wright 

Weston 3.4913.0680.78     2.20     2.33    1. 64  Wright 

Cold  Bokkeveld..  .  .    25.23  0.38?  93.11     2.42     0.84  3  .25  Wright 

SUMMARY  OF  ANALYSES  OF  GASES  FROM  IRON  METEORITES 

Lenarto 2.85  85.68    4.46     9.86   ....   Graham 

Rowton 6.3877.78     5.15     7.34     9.72 Flight 

Red  River 1.2976.79     8.5914.62     Wright 

Charlotte '2.2071.4013.3015.30     Wright 

Shingle  Springs 0.9768.81   13.64  12.47     5.08    ....   Wright 

Cranbourne 3594579     o.  12  31 .88  17.66  4.55  Flight 

Tazewell 3.17  42.66  14.40  41.23     1 .71    ....   Wright 

Staunton 3.17  35.83     9.75  38.33    16.09   ••••   Mallet 

Toluca 1.85   14.54    6.4071.05     5.63  2.35  Chamberlin 

As  to  the  manner  in  which  gases  are  held  by  meteorites  it 
would  be  simplest  to  suppose  that  the  gases  occupy  cavities 
in  the  minerals  of  the  meteorites,  but  microscopic  examina- 
tion shows  very  few  such  cavities.  On  account  of  the  lack 
of  such  cavities,  Travers*  thought  that  the  gases  obtained 
from  meteorites  must  be  of  wholly  secondary  origin,  being 
formed  in  the  process  of  heating  the  meteorites  for  analysis, 
since  it  is  known  that  the  action  of  FeO  oil  water  can  pro- 
duce hydrogen  and  that  of  FeO  on  CO2,  carbon  monoxide. 
Since,  however,  water  is  lacking  in  meteorites  and  CO2  is  a 
gas,  the  supposition  is  not  satisfactory.  There  is  no  doubt, 
however,  that  chemical  interaction  under  the  influence  of 
heat  may  produce  gases  and  modify  those  already  in  the 
meteorite.  Thus  CO2  is  rapidly  reduced  to  CO  in  contact 
with  heated  iron. 

Occlusion  in  the  manner  in  which  platinum,  for  example, 
holds  hydrogen,  seems  to  be  the  most  reasonable  way  of 
explaining  the  gaseous  content  of  meteorites.  To  be  sure, 
the  nature  of  occlusion  is  itself  mysterious,  it  not  being 
known  whether  it  represents  a  sort  of  solution  or  whether  the 
metals  form  compounds  with  the  gases  which  are  later 
dissociated.  Occlusion  is  known  to  be  in  part  also  dependent 
on  porosity. 

*Proc.  Roy.  Soc.,  1896,  60,  156-160. 


CHAPTER   XII 

CLASSIFICATION  OF  METEORITES 

There  have  been  many  efforts  to  form  a  classification  of 
meteorites  which  should  be  at  the  same  time  practical, 
convenient,  and  accurate.  The  continual  increase  in  the 
number  and  kinds  of  meteorites  since  their  preservation  and 
study  was  first  seriously  attempted  has,  however,  steadily 
complicated  the  problem  and  at  times  it  has  been  a  question 
whether  the  effort  to  produce  a  classification  could  keep 
pace  with  the  increase  in  the  number  of  meteorites. 

The  simple  distinction  of  iron  from  stone  meteorites  was 
made  at  an  early  time,  having  been  suggested  by  Klaproth 
in  1807,  and  this  fundamental  distinction  has  been  observed 
by  all  later  classifiers,  though  with  variations.  Maskelyne 
in  1863  divided  meteorites  into  the  three  fundamental  classes 
of  stones,  iron-stones,  and  irons,  and  suggested  for  them 
the  since  much-used  terms  of  aerolites,  aerosiderolites,  and 
aerosiderites.  The  last  term  is  usually  shortened  to  sider- 
ites.  Daubree,  in  1867,  basing  his  classification  on  the  pres- 
ence or  absence  of  iron,  divided  meteorites  into  siderites 
and  asiderites,  although  the  latter  group  is  very  small.  The 
siderites  Daubree  subdivided  into  those  consisting  wholly 
of  iron  and  those  consisting  of  iron  and  silicates.  The  first 
he  called  holosiderites,  the  second  he  subdivided  into  sys- 
siderites  and  sporadosiderites.  The  sporadosiderites  he  sub- 
divided again  into  three  groups  according  to  decreasing 
quantities  of  iron. 

Of  further  efforts  to  subdivide  meteorites  into  groups  sub- 
ordinate to  the  great  groups  of  iron  and  stones  two  systems 
have  found  chief  adoption  in  later  years,  and  of  these  one 
is  gradually  receiving  the  wider  acceptance.  The  first  of 
these  systems  was  an  elaboration  by  Meunier  of  Daubree's 
system,  and  consisted  of  adopting  certain  falls  as  types  for 
groups.  Of  these  groups  there  were  in  Meunier's  latest  class- 

107 


198  METEORITES 

ification  62.  The  second  system  is  an  outgrowth  of  the  sug- 
gestions of  various  German  authorities  of  whom  Gustave 
Rose  was  perhaps  the  first.  In  1862  he  suggested  a  class- 
ification for  the  stones  based  on  their  mineralogical  compo- 
sition and  proposed  names  for  the  different  groups  which 
have  been  widely  adopted.  The  first  division  of  the  stones 
was  based  on  the  presence  or  absence  of  chondri.  Those 
without  chondri,  the  achondrites,  as  they  were  called,  were 
subdivided  into  meteorites  composed  of  single  minerals  and 
those  consisting  of  two  or  more  minerals.  The  group  con- 
sisting of  augite  and  anorthite  was  designated  as  eukrites 
from  two  Greek  words  meaning  well-defined.  Other  groups 
were  designated  by  names  of  early  investigators  such  as 
Chladni  and  Howard.  The  meteorites  containing  chondri, 
known  as  chondrites,  were  divided  into  groups  based  on 
color  or  structure.  This  classification,  elaborated  later  by 
Tschermak  and  Brezina,  has  come  into  general  use  and 
furnishes  perhaps  the  most  convenient  method  which  is  at 
present  available  of  grouping  meteorites  according  to  physi- 
cal characters. 

The  classification  in  its  latest  form  as  given  by  Brezina* 
is  here  shown: 

ROSE-TSCHERMAK-BREZINA  SYSTEM  OF  METEORITE 

CLASSIFICATION 
I.  STONES.     Silicates  prevalent. 

A.  ACHONDRITES 

Stones  poor  in  iron.     In  the  main  without  round  chondri. 

1.  Chladnite.     (Chi).     Chiefly  bronzite. 

2.  Chladnite,  Veined.     (Chla).     Bronzite   with    black   or 

metallic  veins. 

3.  Angrite.     (A).     Chiefly  augite. 

4.  Chassignite.     (Cha).     Chiefly  olivine. 

5.  Bustite.     (Bu).     Bronzite  with  augite. 

6.  Amphoterite.     (Am).     Bronzite  with  olivine. 

7.  Rodite.     (Ro).     Bronzite  with  olivine,  breccia-like. 

8.  Eukrite.     (Eu).     Augite  with  anorthite. 

*Proc.  Am.  Phil.  Soc.,  1904,  53,  211-247. 


CLASSIFICATION   OF   METEORITES  199 

9.    Shergottite.      (She).     Augite  with  maskelynite. 

10.  Howardite.      (Ho).     Bronzite,     olivine,     augite,     and 

anorthite. 

11.  Howardite,     Breccia-like.     (Hob).     Bronzite,     olivine, 

augite,  and  anorthite. 

B.    CHONDRITES 

Bronzite,    olivine,   and    nickel-iron.     Round,    rounded,    or 
polyhedric  chondri 

12.  Howarditic    Chondrite.      (Cho).     Polyhedric    segrega- 

tions preponderating,  round  chondri  scarce.     Crust 
bright  in  parts. 

13.  Howarditic   Chondrite,   Veined.     (Choa).     Polyhedric 

segregations   predominating,    round   chondri   scarce. 
Metallic  or  black  veins. 

14.  White  Chondrite.     (Cw).     White,  rather  friable  mass 

with  few,  chiefly  white,  chondri. 

15.  White  Chondrite,  Veined.  (Cwa).    White,  rather  friable 

mass   with    few,    chiefly   white    chondri.     Black   or 
metallic  veins. 

16.  White  Chondrite,  Breccia-like.    (Cwb).     White,  rather 

friable  mass  with  few,  chiefly  white  chondri,  breccia- 
like. 

17.  Intermediate  Chondrite.     (Ci).     Firm,  polishable  mass 

with  white  and  gray  chondri  breaking  with  matrix. 

1 8.  Intermediate    Chondrite,  Veined.     (Cia).     Firm,  pol- 

ishable mass,  with  white  and  gray  chondri  breaking 
with  matrix.     Black  or  metallic  veins. 

19.  Intermediate  Chondrite,   Breccia-like.      (Cib).      Firm 

polishable  mass  with  white  and  gray  chondri  break- 
ing with  matrix,  breccia-like. 

20.  Gray  Chondrite.    (Cg).     Firm,  gray  mass,  chondri  of 

various  kinds  breaking  with  matrix. 

21.  Gray   Chondrite,  Veined.     (Cha).     Firm,  gray   mass. 

Chondri    of   various    kinds    breaking   with    matrix, 
veined. 

22.  Gray    Chondrite,    Breccia-like.     (Cgb).     Firm,     gray 

mass.     Chondri    of    various    kinds    breaking    with 
matrix,  breccia-like. 


200  METEORITES 

23.  Orvinite.     (Co).     Black,  infiltrated  mass:  fluidal  struc- 

ture; surface  uneven;  crust  incomplete. 

24.  Tadjerite.     (Ct).     Black,  semi-glassy,   crust-like  mass 

with  similar  surface. 

25.  Black  Chondrite.    (Cs).    Dark  or  black  mass.    Chondri 

of  various  kinds  breaking  with  matrix. 

26.  Black  Chondrite,  Veined.    (Csa).     Dark  or  black  mass. 

Chondri  of  various  kinds  breaking  with  matrix; 
veined. 

27.  Ureilite.    (U).    Black  mass,  chondritic  or  granular,  iron 

in  veins  or  incoherent. 

28.  Carbonaceous    Chondrite.     (K).     Dull    black,    friable 

chondrite  with  free  carbon  and  of  low  specific  gravity. 
Nickel-iron  nearly  or  wholly  wanting. 

29.  Carbonaceous     Chondrite,     Spherulitic.      (Kc).      Dull 

gray  or  black,  friable  mass  with  free  carbon;  chondri 
not  breaking  with  matrix.  Nickel-iron. 

30.  Carbonaceous  Chondrite,  Spherulitic,  Veined.     (Kca). 

Dull  black,  firm  mass  with  free  carbon;  chondri 
not  breaking  with  matrix.  Nickel-iron.  Metallic 
veins. 

31.  Spherulitic  Chondrite.     (Cc).     Friable  mass  with  firm 

chondri  of  radiate  structure,  not  breaking  with 
matrix. 

32.  Spherulitic   Chondrite,  Veined.     (Cca).     Friable  mass 

with  firm  chondri  of  radiate  structure,  not  breaking 
with  matrix;  black  or  metallic  veins. 

33.  Spherulitic  Chondrite,   Breccia-like.     (Ccb).     Friable, 

breccia-like  mass  with  firm  chondri  of  radiate  struc- 
ture, not  breaking  with  matrix. 

34.  Ornansite.     (Ceo).     Friable  mass  of  chondri. 

35.  Ngawite.    (Ccn).     Friable,  breccia-like  mass  of  chondri. 

36.  Spherulitic    Chondrite,    Crystalline.     (Cck).     Slightly 

friable,  crystalline  mass  with  firm  chondri  of  radiate 
structure,  some  breaking  with  matrix. 

37.  Spherulitic    Chondrite,    Crystalline,   Veined.     (Ccka). 

Slightly  friable,  crystalline,  veined  mass  with  firm 
chondri  of  radiate  structure,  some  breaking  with 
matrix. 


CLASSIFICATION   OF   METEORITES  201 

38.  Spherulitic  Chondrite, Crystalline,  Breccia-like.  (Cckb). 

Slightly  friable,  crystalline,  breccia-like  mass  with 
firm  chondri  of  radiate  structure,  breaking  with 
matrix. 

39.  Crystalline  Chondrite.     (Ck).     Hard,  crystalline  mass 

with  firm  chondri  of  radiate  structure,  breaking  with 
matrix. 

40.  Crystalline  Chondrite,  Veined.     (Cka).     Hard,  crystal- 

line, veined  mass  with  firm  chondri  of  radiate  struc- 
ture, breaking  with  matrix. 

41.  Crystalline     Chondrite,     Breccia-like.     (Ckb).     Hard, 

crystalline,  breccia-like  mass  with  firm  chondri  of 
radiate  structure,  breaking  with  matrix. 

C.  ENSTATITE-ANORTHITE-CHONDRITES 

Enstatite,  anorthite  and  nickel-iron  with  round  chondri 

42.  Crystalline       Enstatite-Anorthite-Chondrite.       (Cek). 

Hard  crystalline  mass  with  firm  chondri  of  radiate 
structure,  breaking  with  matrix. 

D.  SIDEROLITES 

Transition  from  stones  to  irons.     Nickel-iron  in  the  mass 
cohering;  on  sections  separated 

43.  Mesosiderite.     (M).     Crystalline  olivine  and  bronzite 

with  nickel-iron. 

44.  Grahamite.     (Mg).     Crystalline  olivine,  bronzite  and 

plagioclase  with  nickel-iron. 

45.  Lodhranite.     (Lo).     Granular,  crystalline  olivine  and 

bronzite  with  nickel-iron. 

II.  IRONS.     Metallic    constituents    prevalent    or    forming 

entire  mass 

E.  LITHOSIDERITES 

Transition  from  stones  to  irons.     Nickel-iron  cohering  in 
mass  and  in  sections. 

46.  Siderophyre.     (Si).     Grains  of  bronzite  with  accessory 

asmanite  in  trias. 

47.  Pallasite,  Krasnojarsk  group.     (Pk).    Rounded  crystals 

of  olivine  in  trias. 


202  METEORITES 

48.  Pallasite,  Rokicky  group.     (Pr).     Polyhedric  crystals  of 

olivine,  partly  broken,  and  fragments  separated  by 
nickel-iron. 

49.  Pallasite,  Imilac  group.     (Pi).     Olivine  crystals  fissured 

and  compressed. 

50.  Pallasite,   Bitburg  group.      (Pb).     Olivine  crystals  in 

fine,  brecciated  trias. 

F.  OCTAHEDRITES 

51.  Kamacite,  taenite,  and  plessite  (trias),  in  lamellae  and 

concamerations  of  the  four  octahedral  faces. 

52.  Finest  Octahedrite.     (Off).     Lamellae  up  to  0.2  mm. 

thickness. 

53.  Fine  Octahedrite,  Victoria  group.    Ofv.     Lamellae  of 

troilite  and  schreibersite  in  fine  trias. 

54.  Fine  Octahedrite.    (Of).    Thickness  of  lamellae  0.2-0.4 

mm. 

55.  Fine  Octahedrite,  Fused.    (Ofe).    Figures  disordered  by 

fusion;  points  instead  of  troilite  lamellae. 

56.  Medium  Octahedrite.      (Om).     Thickness  of  lamellae 

0.5-1  mm. 

57.  Medium  Octahedrite,  Fused.     (Ome).     Figures  disor- 

dered by  fusion.     Points  instead  of  taenite  lamellae. 

58.  Coarse  Octahedrite.     (Og).     Thickness  of  lamellae  1.5- 

2.0  mm. 

59.  Coarse  Octahedrite,  Fused.    (Oge).    Figures  disordered 

by  fusion.     Points  instead  of  taenite  lamellae. 

60.  Coarsest  Octahedrite.     (Ogg).     Thickness  of  lamellae 

2.5  mm.  and  more. 

61.  Breccia-like  Octahedrite,  Netschajevo  group.      (Obn). 

Medium    Octahedrite    brecciated    with    nodules    of 
silicate. 

62.  Breccia-like  Octahedrite,  Kodaikanal  group.      (Obk). 

Fine  octahedrite,  brecciated  with  nodules  of  silicate. 

63.  Breccia-like     Octahedrite,     Copiapo     group.     (Obc). 

Coarsest    Octahedrite    brecciated    with    nodules    of 
silicate. 

64.  Breccia-like  Octahedrite, Zacatecas  group,  (Obz).  Octa- 

hedral nodules  breccia-like,  with  spherules  of  troilite. 


CLASSIFICATION   OF   METEORITES  203 

65.  Breccia-like  Octahedrite,  N'goureyma  group.     (Obzg), 

Fused  and  drawn-out  iron  of  the  Zacatecas  group. 

G.  HEXAHEDRITES 

Structure  and  cleavage  hexahedral 

66.  Normal  Hexahedrite.     (H).    Neumann  lines,  not  granu- 

lar. 

67.  Grained  Hexahedrite.     (Ha).     Structure  and  cleavage 

running  through  the  whole  mass.     The  mass  consists 
of  grains  with  differently  oriented  spangling. 

68.  Brecciated  Hexahedrite.    (Hb).   Mass  containing  differ- 

ently oriented  hexahedral  grains. 

H.  ATAXITES 

Structure  interrupted 

69.  Cape  group.    (Dc.)   Rich  in  nickel;  sharp  (hexahedral?) 

etching  bands  in  dull  mass. 

70.  Shingle  Springs  group.   (Dsh).    Rich  in  nickel;  indistinct 

parallel  blebs. 

71.  Babbs  Mill  group.     (Db).      Rich  in  nickel;  lustreless, 

homogeneous  mass. 

72.  Linnville  group.     (Dl).     Rich   in   nickel;    meandering 

veined  or  latticed. 

73.  Nedagolla  group.      (Dn).     Poor  in  nickel,  grained,  no 

ridges. 

74.  Siratik  group.     (Ds).     Poor  in  nickel;  shows  ridges,  in- 

cisions or  enveloped  rhabdites. 

75.  Primitiva  group.     (Dp).     Poor  in  nickel;  silky  streaks 

and  luster. 

76.  Muchachos  group.      (Dm).      Poor  in  nickel,  grained, 

porphyritic  with  forsterite. 

While  as  a  means  of  distinguishing  meteorites  by  their 
more  obvious  physical  characters  this  classification  is  per- 
haps as  convenient  as  any  yet  devised,  it  is  chiefly  unsatis- 
factory in  its  subdivision  of  the  great  group  of  chondrites, 
since  the  classes  are  distinguished  only  by  color,  a  character 
which  can  be  of  little  fundamental  importance,  although  it 
is  true  that  meteorites  consisting  largely  of  enstatite  or  hy- 


204  METEORITES 

persthene  are  likely  to  be  of  somewhat  lighter  color  than 
those  largely  composed  of  chrysolite. 

In  an  effort  to  establish  a  quantitative  classification  the 
characters  of  which  should  more  sharply  and  surely  divide 
meteorites,  the  writer  has  applied  to  meteorites  the  prin- 
ciples of  the  American  quantitative  classification  of  rocks. 
As  the  details  of  this  classification  are  somewhat  too  elabor- 
ate for  the  limits  of  this  work  the  reader  is  referred  to  the 
original  publication  in  which  the  classification  is  described 
in  full.* 

*Pubs.  Field  Museum,  1911,  Geol.  Ser.,  3,  195-228. 


CHAPTER   XIII 

ORIGIN  OF  METEORITES 

The  origin  of  meteorites  has  always  been  a  subject  of 
great  interest,  perhaps  that  of  greatest  interest  connected 
with  them.  Yet  it  is  a  subject  in  regard  to  which  little 
satisfactory  information  can  be  given.  Two  lines  of 
inquiry  seem  open,  the  first  to  endeavor  to  decipher  the 
origin  of  meteorites  from  details  of  their  structure  and  com- 
position, and  the  second  to  follow  them  back  along  their 
celestial  paths  as  far  as  possible  into  the  regions  of  space  from 
whence  they  came.  So  far  as  the  structure  and  composi- 
tion of  meteorites  are  concerned  there  can  be  no  doubt  that 
meteorites  are  of  igneous  origin.  All  terrestrial  analogies 
indicate  that  in  cosmic  furnaces  of  some  sort,  fires  glowed 
which  gave  meteorites  the  structures  which  they  present  to 
us.  As  between  iron  and  stone  meteorites,  some  differences 
of  conditions  existed  which  gave  them  somewhat  different 
structures,  since  the  iron  meteorites  show  well-formed  crys- 
tallization as  if  they  had  been  maintained  in  a  uniform 
condition  of  temperature,  and  that  sufficient  to  keep  them 
liquid  or  viscous  for  a  long  time,  while  the  stone  meteorites 
exhibit  glass,  chondritic  structures,  and  other  evidences  of 
a  hasty  crystallization  which  indicate  rapid  cooling.  Yet 
the  substance  of  the  two  kinds  of  meteorites  tends  to  grade 
from  one  to  the  other;  the  nickel-iron  and  piyrrhotite  of 
the  stone  meteorites  is  the  same  as  that  of  the  iron  mete- 
orites, and  the  silicates  of  the  stone  meteorites  suffer  grad- 
ual diminution  as  they  pass  to  the  iron  meteorites.  Such 
facts  suggest  that  the  iron  and  stone  meteorites  may  have 
been  associated  in  some  cosmic  mass,  the  materials  of  which 
were  assorted  according  to  their  specific  gravity.  In  such 
a  mass  the  metal  would  be  at  the  center  while  the  lighter 
silicates  would  be  at  the  surface.  In  the  cooling  of  such  a 
mass  the  exterior  or  siliceous  portion  would  congeal  more 

205 


206  METEORITES 

quickly  than  the  interior  metallic  nucleus.  The  latter 
would  thus  possess  conditions  favoring  more  nearly  com- 
plete crystallization.  So  far  as  the  substance  of  meteorites 
is  concerned,  it  may  be  noted  that  their  principal  ingredi- 
ents, nickel-iron,  chrysolite,  and  bronzite  are  substances 
which  have  all  about  the  same  freezing  point  —  between 
1400°  and  1500°  C.  What  significance  this  fact  may  have 
in  indicating  the  origin  of  meteorites  the  writer  is  unable  to 
say,  but  it  seems  probable  that  it  has  some  meaning. 

The  fact  that  the  silicates  of  meteorites,  such  as  chrysolite, 
enstatite  and  feldspar,  constitute  some  terrestrial  volcanic 
rocks,  has  perhaps  given  rise  to  the  suggestion  made  at  dif- 
ferent times  that  meteorites  may  represent  matter  which 
was  originally  ejected  by  the  earth's  volcanoes  and  is  falling 
back  again.  Except  for  the  similarity  of  material,  there 
seems  to  be  no  good  reason  for  such  an  assumption.  Even 
the  similarity  of  material  fails  so  far  as  the  iron  meteorites 
are  concerned,  for  no  such  substance  as  that  of  the  iron 
meteorites  has  ever  been  ejected  by  terrestrial  volcanoes. 
The  native  iron  of  Greenland  somewhat  resembles  meteoritic 
iron  but  while  seemingly  of  eruptive  origin  it  shows  no 
evidence  of  ever  having  been  connected  with  explosive  vol- 
canoes. Moreover,  while  analogous  to  meteoritic  iron,  the 
Greenland  iron  shows  marked  differences  which  enable  it 
readily  to  be  distinguished.  The  percentage  of  nickel  is 
lower  in  the  Greenland  iron  than  in  any  meteoritic  iron,  un- 
less a  few  unsatisfactory  analyses  be  accepted,  the  percent- 
age of  carbon  is  higher,  and  no  typical  octahedral  or  other 
meteoritic  figures  are  exhibited  on  etching. 

Another  meteoritic  feature  not  found  terrestrially  is  that 
of  chondritic  structure.  While  the  spherulites  sometimes 
found  in  volcanic  rocks  partially  resemble  chondri  there  are 
many  features  which  are  lacking  and  they  cannot  be  re- 
garded as  identical.  Even  if  materials  exactly  similar  to 
those  of  meteorites  could  be  found  upon  the  earth,  it  would 
still  be  necessary  to  bear  in  mind,  before  a  terrestrial  origin 
of  meteorites  could  be  accepted,  that  terrestrial  volcanoes 
have  never  been  known  to  exert  the  great  energy  which 
would  be  necessary  in  order  to  throw  material  out  beyond  the 


ORIGIN   OF   METEORITES 


207 


range  of  the  earth's  attraction.  To  do  this,  as  shown  by  the 
accompanying  figure  (Fig.  59)  a  velocity  of  at  least  five  miles 
per  second  must  be  given  to  a  body.  To  produce  the 
velocity  which  meteorites  have,  the  force  must  have  been 
even  greater,  since  meteorites  come  to  the  earth  with  plane- 
tary velocities  and  must  have  had  such  velocities  initially. 
There  is  no  reason  to  suppose  that  terrestrial  volcanoes  ever 
exhibited  forces  of  such  intensity  as  this.  Moreover,  if 
terrestrial  volcanoes  have  ever  sent  out  matter  in  this  way, 


FIG.  59. —  Effect  of  earth's  gravitation  on  bodies  of  different  velocities. 


its  quantity,  in  order  to  produce  the  supply  of  meteorites 
which  reaches  the  earth,  must  have  far  exceeded  any  amount 
that  terrestrial  volcanoes  have  yet  been  observed  to  pro- 
duce. Of  the  material  ejected  only  a  very  small  quantity 
would  be  likely  to  be  drawn  into  the  range  of  the  earth's 
attraction  again. 

Since  the  moon's  surface  is  apparently  dotted  with  large 
volcanoes,  though  they  appear  to  be  at  the  present  time 
extinct,  it  has  been  suggested  that  meteorites  are  material 
ejected  by  the  volcanoes  of  the  moon.  This  is  also  an  as- 
sumption which  is  discredited  by  available  evidence  and 
the  same  objections  apply  to  this  view  as  to  that  which 
supposes  meteorites  to  have  come  from  terrestrial  volcanoes. 
The  forces  and  quantity  of  matter  required  to  produce 
meteorites  from  the  moon  would  be  far  beyond  that  likely 
to  have  been  afforded  by  lunar  volcanoes.  Moreover,  the 
velocity  of  lunar  fragments  reaching  the  earth  would  be 
only  six  and  a  half  miles  a  second,  while  meteorites  have 
much  higher  velocities. 


208  METEORITES 

A  possible  origin  of  meteorites  from  the  sun  has  also  been 
suggested.  Objections  to  this  view  are  found  in  the  diffi- 
culty of  conceiving  how  a  globe  in  so  vaporous  and  heated 
a  condition  as  the  sun  would  produce  solid  bodies.  Even 
if  the  sun  has  a  solid  core  from  which  such  bodies  could  start 
they  would  need  to  pass  through  an  atmosphere  of  immense 
heat  before  they  could  arrive  in  free  space,  and  it  seems 
hardly  possible  that  the  solid  nature  of  small  bodies  could 
be  preserved  under  such  conditions.  Moreover  the  paths 
of  many  meteorites  are  much  inclined  to  the  ecliptic,  while 
a  body  ejected  from  the  sun  and  reaching  the  earth  would 
move  in  a  line  parallel  to  the  ecliptic. 

The  class  of  heavenly  bodies  to  which  the  origin  of  meteor- 
ites has  been  most  generally  ascribed  within  recent  years 
is  that  of  the  comets,  (Fig.  60).  Largely  through  the  work 
of  H.  A.  Newton,  the  orbits  of  many  of  the  important  shoot- 
ing star  or  meteor  showers  were  found  to  be  identical  with 
those  of  comets,  these  orbits  being  in  some  cases  those  of 
comets  which  had  disappeared.  Thus  the  August  meteors 
or  Perseids  were  found  to  have  the  same  orbit  as  Tuttle's 
comet  and  the  November  or  Leonids  the  same  as  that  of 
Tempers.  Biela's  comet,  which  disappeared  in  1872,  has 
its  place  in  the  heavens  represented  by  the  Andromedes 
shower.  Accordingly  Newton  believed  and  the  view  has 
been  widely  adopted,  that  the  difference  between  large  and 
small  meteors  is  simply  one  of  size  and  that  a  meteorite  is 
the  solid  product  of  a  large  meteor.  If  the  differences  be- 
tween meteorites  and  star  showers  were  only  those  of  size, 
this  view  might  be  accepted,  but  an  investigation  of  the 
matter  discloses  other  points  of  difference.  Of  these,  per- 
haps the  most  important  one  is  that  meteorites  do  not  fall 
at  the  times  of  the  shooting  star  showers.  A  single  case  is 
known — that  of  the  Mazapil  iron,  which  fell  November  27, 
1885 — of  a  meteorite  falling  at  the  time  of  a  star  shower, 
but  so  isolated  a  case  could  be  accounted  for  purely  as  a 
coincidence.  If  meteorites  and  star  showers  have  the  same 
origin  star  showers  would  be  expected  to  yield  large  num- 
bers of  meteorites.  The  data  given  under  times  of  fall, 
page  39,  show  that  the  times  when  meteorite  falls  are  most 


ORIGIN   OF   METEORITES 


209 


210  METEORITES 

abundant  are  not  those  of  star  showers.  Hence  it  seems 
that  if  comets  produce  meteorites,  they  are  comets  of  a 
different  nature  from  those  which  produce  star  showers  or 
shooting  stars  (Fig.  61). 

According   to   the  meteoritic   hypothesis   of  J.  Norman 
Lockyer,  meteorites  are  the  primary  dust  of  the  universe 


FIG.  61. —  A  shooting  star  trail,  showing  sudden  increase  in  brightness.     Yerkes 
Observatory.     June  7,  1899. 

out  of  which  all  cosmic  bodies  have  been  produced.  "All 
self-luminous  bodies  in  the  celestial  spaces,"  according  to 
this  hypothesis,  "are  composed  either  of  swarms  of  meteor- 
ites or  of  masses  of  meteoritic  vapor  produced  by  heat.  The 
heat  is  brought  about  by  the  condensation  of  meteor  swarms 
due  to  gravity,  the  vapor  being  finally  condensed  into  a 
solid  globe."  *  According  to  this  theory  the  light  of  the 
nebulae  is  due  to  constant  collisions  of  the  constituent 

*The  Meteoritic  Hypothesis,  1890,  527. 


ORIGIN   OF   METEORITES  211 

meteorites.  G.  H.  Darwin  discussed  the  mechanical  con- 
dition of  such  a  swarm  and  concluded  that  it  would  be 
dynamically  analogous  to  a  gas.  Chamberlin*  showed 
that  such  a  swarm  would  probably,  on  account  of  the  fre- 
quent and  violent  collisions  of  its  meteoritic  components, 
pass  into  the  gaseous  condition  and  thus  produce  a  body  in 
no  way  differing  from  the  familiar  gaseous  nebula.  Inquiry 
was  further  carried  on  by  Chamberlin  to  determine  whether 
some  other  form  of  meteoritic  assemblage  might  be  postu- 
lated which  might  produce  in  its  evolution  such  bodies  as 
the  earth  or  others  of  the  solar  system.  He  reached  the 
conclusion  that  formidable  difficulties  in  preparing  such  a 
hypothesis  would  be  found  in  the  high  ratio  of  the  kinetic 
energy  of  meteorites  to  their  mutual  gravitation,  in  the 
sparseness  of  distribution  of  meteoritic  matter,  and  in  the 
enormous  period  of  time  necessary  for  such  an  assemblage. 
Chamberlin  concluded,  however,  that  if  a  meteoritic  swarm 
could  by  any  means  acquire  a  large  mass  the  probabilities 
of  its  holding  its  own  members  and  capturing  additional 
meteorites  would  be  very  favorable.  No  form  of  the  me- 
teoritic hypothesis  which  has  yet  been  propounded  seems 
able  to  explain  the  manner  in  which  meteorites  are  produced. 
Another  origin  suggested  for  meteorites  is  that  they  are 
parts  of  a  shattered  planet  or  planetoid.  Such  an  origin 
would,  according  to  the  author's  view,  be  that  which  is  in- 
dicated as  most  probable  by  the  structure  and  composition 
of  meteorites.  Further,  all  evidence  seems  to  indicate  that 
meteorites  are  fragments  of  some  pre-existing  body  rather 
than  independent  celestial  bodies.  How  large  the  bodies 
may  have  been  of  which  meteorites  once  formed  a  part 
is  of  course  uncertain.  The  rings  of  Saturn  (Fig.  62)  are 
known  to  be  made  up  of  multitudes  of  small,  solid  bodies, 
and  it  may  be  bodies  of  this  nature  that  are  the  source  of 
supply  of  meteorites.  The  planetoids,  some  of  which  are 
known  to  be  of  irregular  form,  are  another  possible  source. 
Two  chief  difficulties  arise  in  ascribing  the  origin  of  mete- 
orites to  disintegrated  bodies  within  the  solar  system,  (i) 
the  difficulty  of  conceiving  of  a  disintegrating  force,  and 

*Geology,  1906,  2,  14. 


212  METEORITES 

(2)  the  difficulty  of  explaining  the  inclination  of  the  orbits 
of  some  meteorites  to  the  ecliptic. 

So  far  as  the  first  difficulty  is  concerned,  it  seems  hardly 
likely  that  a  solid,  independent  form  is  always  the  final  stage 
in  the  evolution  of  matter.  The  fact  that  comets  break  up 
shows  that  some  disruptive  forces  exert  their  influence 
among  cosmic  bodies  in  amount  sufficient  to  start  them  in 


FIG.  62. —  The  planet  Saturn  and  its  rings.  These  rings  are  composed  of  multi- 
tudes of  small  solid  bodies  which  may  be  of  a  meteoritic  nature.  From  draw- 
ing by  Barnard,  July  7,  1898' 

new  courses.  The  so-called  rills  upon  the  moon's  surface 
indicate  the  existence  of  disruptive  forces  of  some  kind  in 
that  satellite  which  might  gradually  disintegrate  it.  A 
probable  source  of  disruption  has  been  suggested  by  Cham- 
berlin*  as  being  found  in  the  differential  attraction  pro- 
duced by  the  passage  of  a  small  body  within  a  certain 
distance  of  a  larger,  dense  one.  The  distance  within  which 
disruption  would  take  place  for  incompressible  fluids  of  the 
same  density  is  given  by  Roche  (Roche's  limit)  as  2.44  times 
the  radius  of  the  large  body.  Since  solid  bodies  possess 
some  internal  elasticity  it  is  probable  that  the  passage  of  a 

*Astrophys.  Jour.,  1900,  14,  17-40. 


ORIGIN   OF   METEORITES  213 

larger  body  at  a  somewhat  greater  distance  than  this  even 
would  disrupt  a  smaller  one.  Here  then  is  a  possible  shat- 
tering force.  Another  would  be  found  in  collisions  of  two 
bodies,  but  these  would  be  less  numerous  than  approaches, 
and  taking  place  between  bodies  moving  at  planetary 
velocities  would  be  likely  to  generate  so  much  heat  as  to 
vaporize  the  substance  of  the  colliding  bodies.  The  passage 
of  a  large  body  near  a  small  one  would,  in  addition  to 
exerting  a  disrupting  effect,  tend  to  change  the  orbit  of  the 
smaller  body.  Such  a  change  has  often  been  observed  to 
be  produced  in  the  orbit  of  a  comet  by  its  passage  near  a 
planet.  Hence  a  comet  passing  near  a  smaller  body  might 
change  the  orbit  of  the  latter,  drawing  it  out  of  the  ecliptic 
and  giving  it  a  hyperbolic  or  even  parabolic  form.  By  this 
means  the  inclination  of  some  meteoritic  orbits  may  have 
been  produced. 

It  was  the  opinion  of  Newton*  that  the  orbits  of  the 
larger  meteorites  are  allied  much  more  closely  with  the 
group  of  comets  of  short  period  than  with  those  of  parabolic 
orbits,  and  this  conclusion  seems  to  point  to  an  origin  of 
meteorites  within  the  solar  system.  W.  H.  Pickering  f 
asserts  that  the  orbits  of  the  majority  of  meteorites  do  not 
even  reach  as  far  as  the  zone  of  planetoids.  On  the  other 
hand,  Schiaparelli  felt  convinced  from  mathematical  con- 
siderations that  meteorites  come  from  the  world  of  fixed 
stars.  The  meteorite  of  Pultusk  he  stated  came  from  the 
constellation  of  the  Great  Bear  and  that  of  Knyahinya  from 
Pisces.  It  is  evident  that  more  study  of  the  orbits  and 
velocities  of  meteorites  is  needed  before  a  satisfactory  de- 
cision as  to  their  point  of  origin  can  be  reached. 

*Am.  Jour  Sci.,  1888,  3,  36,  13. 
fPop.  Astron.,  1910,  18,  245. 


CHAPTER   XIV 

TERRESTRIAL  RELATIONS 

It  has  already  been  remarked  that  stone  meteorites 
resemble  certain  volcanic  rocks  of  the  earth.  The  rocks 
which  they  resemble  are  chiefly  terrestrial  peridotites, 
Iherzolites,  wehrlites,  etc.,  which  are  rocks  composed 
largely  of  chrysolite  or  of  chrysolite  and  pyroxene.  From 
these  the  chondritic  meteorites  essentially  differ  only  in  their 
content  of  metallic  grains  and  in  their  chondritic  structure. 
From  terrestrial  dolerites,  the  eukritic  meteorites  differ 
scarcely  at  all.  The  iron  meteorites  have  (as  already  noted) 
a  terrestrial  counterpart  in  the  masses  of  native  iron  found 
in  Greenland,  though  the  latter  contain  less  nickel  and  more 
carbon  than  iron  meteorites  and  do  not  exhibit  Widmann- 
statten  figures  on  etching.  But  many  of  the  important  rock 
forming  minerals  of  the  crust  of  the  earth  are  either  lacking 
or  play  an  insignificant  part  in  the  formation  of  meteorites. 
Such  are  quartz,  orthoclase,  the  acid  plagioclases,  the  micas, 
amphiboles,  leucite,  and  nepheline.  Vice  versa,  the  chief 
mineral  constituents  of  meteorites  do  not  occur  in  large 
amount  in  the  earth's  crust.  Such  are  nickel-iron,  the  orth- 
orhombic  pyroxenes,  and  chrysolite.  Looked  at  chemically 
it  may  be  said  that  terrestrial  rocks  abound  in  silica  (free 
and  combined),  lime,  alumina,  and  alkalies,  while  meteorites 
abound  in  iron,  nickel,  and  magnesia. 

These  differences  will  not  appear  so  great  if  we  remember 
that  changes  may  have  been  wrought  in  the  composition  of 
the  earth's  crust  which  have  not  taken  place  in  meteorites. 
The  active  agents  water  and  oxygen  which  are  lacking  in 
meteorites  are  continually  working  upon  the  earth's  crust 
to  change  its  composition.  Also  the  carbonic  acid  of  the 
earth's  atmosphere  would  act  upon  metasilicates  as  follows: 

MOSiO2 +CO2  =  SiO2 + MOCO2 
or  upon  the  orthosilicates: 

214 


TERRESTRIAL   RELATIONS  215 

(MO)  2SiO2 + 2CO2  =  SiO2 + 2MOCO2 

Here  M  represents  any  base.  Such  agencies  working  for 
long  periods  of  time  in  connection  with  gravitational  move- 
ments might  produce  considerable  modification  of  the  com- 
position of  the  earth's  crust  as  compared  with  its  original 
composition.  It  should  be  remembered  too  that  the  crust 
of  the  earth  to  a  depth  of  ten  miles,  which  is  the  only  por- 
tion with  which  we  are  accquainted,  constitutes  only  about 
Viao  part  of  the  earth  as  a  whole.  In  comparing,  therefore, 
the  composition  of  the  crust  of  the  earth  with  that  of  mete- 
orites, a  few  meteorites  may  be  sufficient  to  represent  the 
known  crust.  Taking  for  this  purpose  the  composition  of 
four  well-known  meteorites,  those  of  Petersburg,  Stannern, 
Juvinas,  and  Frankfort,  which  meteorites  also  nearly  cor- 
respond in  specific  gravity  with  the  earth's  crust,  the  com- 
parison with  the  average  composition  of  the  earth's  crust  is 
as  follows: 


SiO2                       .... 

I 

Four 
meteorites       t 
4Q.Sc 

II 

Average  of 
errestrial  rocks 

18  24 

A12O3 

II  .  14 

15  80 

Fe203  \ 

18.87 

7    21 

FeO    / 
MgO    

3.84 

CaO    

0.44 

C.22 

Na2O  

'     TT 
O.63 

3  .01 

K2O  

o.  14 

H2O 

I    7Q 

TiO2 

O  O3 

I    O4 

P2O5 

o  07 

•27 

100.00  100.58 

A  comparatively  slight  enrichment  in  some  ingredients 
of  the  above  meteoritic  magma  and  impoverishment  in 
others,  which  might  be  carried  on  progressively,  would  pro- 
duce in  time  a  composition  like  that  of  the  earth's  crust. 

Further,  if  it  were  possible  to  compare  the  composition 
of  meteorites  with  that  of  the  earth  as  a  whole  it  is  possible 
that  an  even  greater  similarity  would  be  found  to  exist. 
The  average  composition  of  meteorites  as  determined  by 
the  sum  of  all  reliable  analyses  is  as  follows:* 

*Farrington  Pubs.  Field  Museum,  1910,  Geol.  Ser.,  3,  213. 


216  METEORITES 


AVERAGE    COMPOSITION    OF    METEORITES 

Fe  ...............................................     68.43 

SiO2  .............................................      1  1  .  07 

Ni  .........................  J  .....................       6.44 

MgO  .............................................       6.33 

FeO  .............................................       4-55 

A1203  .............................................  74 

CaO  ..............................................  65 


Na2O  .............................................  23 

P  .........................................  ........  H 

CroO3  .............................................  12 

Fe2O3  .............................................  ii 

NiO  ..............................................  06 

K20  ..............................................  05 

MnO  .............................................  04 

C  ......  .  ..........................................  04 

Cu  ...............................................  01 

Cr  ................................................  01 

PA  ..............................................  01 

TiOo  ..............................................  01 

SnO2  ..............................................  01 


99.98 
Calculated  as  elements  this  becomes 

Iron 72 . 06 

Oxygen 10. 10 

Nickel 6.50 

Silicon 5  . 20 

Magnesium 3  . 80 

Sulphur 49 

Calcium 46 

Cobalt 44 

Aluminum 39 

Sodium .17 

Phosphorus .14 

Chromium .09 

Potassium .04 

Carbon 04 

Manganese .03 

Other  elements .05 


100.00 


Such  a  mixture  would  have  a  density  very  near  that  of 
the  earth  as  a  whole,  which  is  5.57.  That  the  interior  of 
the  earth  may  be  largely  composed  of  iron  is  indicated  by 
its  rigidity,  which  is  about  that  of  steel,  and  also  by  its 
magnetic  properties.  Also  it  is  well  known  that  some  cause 
must  produce  the  high  specific  gravity  of  the  earth  as  a 
whole  as  compared  with  that  of  its  crust,  since  the  whole 
earth  has  a  specific  gravity  more  than  twice  as  great  as  that 


TERRESTRIAL   RELATIONS  217 

of  its  crust.  The  earth's  interior  must  be  denser  than  its 
exterior,  either  because  the  interior  contains  material  which 
is  inherently  more  dense  or  if  of  originally  light  material, 
because  it  has  been  made  dense  through  pressure.  That  the 
material  of  the  earth's  interior  must  be  subjected  to  enor- 
mous pressures  there  can  be  no  doubt,  though  the  pressure 
increases  in  a  diminishing  ratio  toward  the  center.  We 
have  no  means  of  determining  what  the  effect  of  such  pres- 
sures would  be,  but  no  phenomena  within  our  observation 
indicate  that  the  pressure  would  be  able  to  more  than  dou- 
ble the  density  of  materials  as  would  be  necessary  if  the 
density  of  the  materials  of  the  crust  of  the  earth  were 
changed  to  that  of  the  earth  as  a  whole.  Accordingly  the 
existence  of  inherently  denser  material  in  the  interior  seems 
probable.  The  average  specific  gravity  of  meteorites  seen 
to  fall  is  3.59,  or  calculated  by  the  weight  of  each  fall,  3.65. 
No  calculation  of  the  specific  gravity  of  all  meteoritic  mat- 
ter has  yet  been  made. 

Certain  physical  effects  exerted  upon  the  earth  as  a  whole 
by  the  fall  of  meteorites  and  shooting  stars  should  be  con- 
sidered. It  is  evident  that  the  constant  addition  of  meteoric 
matter  must  cause  a  continual  increase  in  the  size  of  the 
earth  although,  of  course,  at  a  very  slow  rate.  Thus, 
according  to  Young,*  the  meteoric  matter  received  daily 
by  the  earth,  if  we  accept  one  grain  as  the  average  weight  of 
a  shooting  star,  would  be  only  about  one  ton,  after  making 
a  reasonable  addition  for  meteorites.  If  we  multiply  this 
estimate  by  one  hundred,  which  will  certainly  be  liberal, 
then  the  amount  of  meteoric  matter  received  by  the  earth 
in  a  year  would  reach  the  very  respectable  figure  of  36,500 
tons;  and  yet,  even  at  this  rate,  assuming  the  specific  gra- 
vity of  the  average  meteor  as  three  times  of  that  water,  it 
would  take  about  1,000,000,000  years  to  accumulate  a  layer 
one  inch  thick  over  the  earth's  surface. 

Again,  says  Young,  theoretically,  the  encounter  of  the 
earth  with  meteors  must  shorten  the  year  in  three  distinct 
ways: 

*Astronomy,  p.  440. 


218  METEORITES 

First.  By  acting  as  a  resisting  medium,  and  so  diminish- 
ing the  size  of  the  earth's  orbit,  and  indirectly  accelerating 
its  motion,  in  the  same  manner  as  is  supposed  to  happen  with 
Encke's  comet. 

Second.  By  increasing  the  attraction  between  the  earth 
and  the  sun  through  the  increase  of  their  masses. 

Third.  By  lengthening  the  day  —  the  earth's  rotation 
being  slower  by  the  increase  of  its  diameter,  so  that  the  year 
will  contain  a  smaller  number  of  days. 

The  whole  effect,  however,  of  the  three  causes  combined, 
does  not  amount  to  i-iooo  of  a  second  in  a  million  years. 
The  diminution  of  the  earth's  distance  from  the  sun,  as- 
suming that  one  hundred  tons  of  meteoric  matter  fall  daily, 
and  also  assuming  that  the  meteors  are  moving  equally  in 
all  directions  with  the  parabolic  velocity  of  twenty-six  miles 
per  second,  comes  out  about  1-20,000  of  an  inch  per  annum. 

Theoretically,  also,  the  same  meteoric  action  should  pro- 
duce a  shortening  of  the  month,  but  an  investigation  by 
Oppolzer  to  see  what  amount  of  meteoric  matter  would 
account  for  the  observed  lunar  acceleration  indicates  that 
it  would  require  an  amount  immensely  greater  than  that 
actually  received  by  the  earth. 

Each  meteor  or  meteorite  brings  to  the  earth  a  certain 
amount  of  heat  developed  in  the  destruction  of  its  motion; 
and  at  one  time  it  was  thought  that  a  very  considerable 
percentage  of  the  total  heat  received  by  the  earth  might  be 
derived  from  this  source.  Assuming,  however,  as  before,  the 
fall  of  one  hundred  tons  of  meteoric  matter  daily  with  an 
average  velocity  of  twenty  miles  per  second  relative  to  the 
earth,  the  whole  amount  of  heat  comes  out  about  1-20 
calorie  per  annum  for  each  square  metre  of  the  earth's  sur- 
face —  as  much  in  a  year  as  the  sun  imparts  to  the  same  sur- 
face in  about  one-tenth  of  a  second. 

One  other  effect  of  meteoric  matter  in  space  should  be 
alluded  to.  It  must  be  necessarily  render  space  imperfectly 
transparent,  like  a  thin  haze.  Less  light  reaches  us  from  a 
remote  star  than  if  the  meteors  were  absent. 

It  would  seem  probable  that  the  constant  fall  of  shooting 
stars  and  small  meteorites  might  produce  an  amount  of 


TERRESTRIAL   RELATIONS  219 

meteoritic  dust  which  would  be  perceptible  in  favorable 
localities  such  as  snow  covered  surfaces  or  the  ocean  bottom. 
Little  of  such  material  has,  however,  ever  been  satisfactorily 
detected.  The  meteoritic  nature  of  some  dusts  collected 
from  the  Greenland  snows  has  been  indicated  by  a  content 
of  nickel,  and  some  spherules  obtained  in  deep  sea  dredging 
seem  to  be  true  meteoritic  chondri  but  observations  of  such 
material  have  been  few. 


CHAPTER   XV 

METEORITE   COLLECTIONS 

For  the  acquirement  of  knowledge  regarding  meteorites, 
collections  of  these  bodies  are  of  the  utmost  value.  The 
size  of  meteorites  is  fortunately  such  as  to  permit  in  most 
cases  their  ready  transportation  to  locations  where  their 
various  features  can  be  minutely  and  carefully  studied. 
This  is  true  even  of  the  great  Cape  York  meteorite  weigh- 
ing nearly  40  tons,  which  was  removed  from  Greenland  to 
New  York  City  (Fig.  63).  Moreover,  the  structure  and 
composition  of  any  individual  meteorite  or  of  the  individ- 
uals of  any  meteorite  fall  are  so  nearly  constant  that  portions 
of  meteorites  may  safely  be  distributed  for  purposes  of  study 
and  thus  facilities  be  provided  in  many  places  for  the  investi- 
gation of  these  bodies. 

Previous  to  the  eighteenth  century,  meteorites  were  rarely 
preserved  by  intention  unless  some  superstition  was  con- 
nected with  their  fall  or  peculiar  characters.  An  iron 
meteorite  which  fell  probably  about  1400  A.  D.  has  ever 
since  that  time  been  preserved  in  the  town  hall  of  Elbogen, 
Bohemia  (Fig.  64).  The  meteorite  was  known  as  the 
"Bewitched  Burggrave"  and  according  to  tradition  the 
mass  represented  a  tyrannical  burggrave  (a  court  official) 
who  had  been  turned  into  iron  in  punishment  for  his  cruelty. 
A  meteoric  stone  weighing  about  300  pounds  which  fell  at 
Ensisheim  in  Alsace,  November  16,  1492,  was  preserved  in 
the  church  of  that  place  at  that  time  by  order  of  the  em- 
peror. A  large  part  of  it  still  hangs  in  the  Town  Hall  of 
Ensisheim.  Several  stones  kept  in  temples  of  the  Greeks 
and  Romans,  including  "Diana  of  the  Ephesians,"  were 
probably  meteorites  but  have  not  been  preserved  to  us. 
The  sacred  stone  which  is  still  worshiped  at  Mecca  is,  how- 
ever, probably  a  meteorite  and  several  meteorites  have  been 
kept  in  Japanese  temples.  The  preservation  of  meteorites 

220 


METEORITE    COLLECTIONS 


221 


" 


222  METEORITES 

for  scientific  purposes  was  not  undertaken  to  any  extent 
until  about  the  beginning  of  the  nineteenth  century,  since 
scientific  men  up  to  that  time  were  unwilling  to  believe  that 
stones  would  fall  from  the  sky.  Careful  investigation  of 
several  such  reputed  occurrences,  however,  notably  that  at 
L'Aigle,  France,  in  1803  established  the  truth  of  the  phe- 
nomenon, and  since  then  collecting  of  these  bodies  has  been 
actively  carried  on. 

The  first  collections  were  formed  in  the  museums  of  the 


FIG.  64. —  Town  hall  at  Elbogen,  Bohemia,  in  which  an  iron  meteorite  called  the 
"Bewitched  Burggrave"  has  hung  (with  some  interruptions)  since  about 
1400  A.  D. 

capitals  of  Europe  and  most  of  these  collections  have  been 
admirably  maintained.  The  Royal  Cabinet  of  Vienna, 
which  afterward  became  the  Natural  History  Museum,  ob- 
tained its  first  meteorite  specimen  in  1747.  Up  to  1805  the 
number  of  falls  represented  there  had  increased  only  to  eight. 
In  1835  it  had  reached  the  number  of  fifty-six  and  in  1856 
was  one  hundred  and  thirty-six.  At  the  present  time  (191 5) 
the  collection  contains  representatives  of  nearly  six  hundred 
and  fifty  falls.  For  many  years  the  collection  was  the  larg- 
est in  the  world  and  its  successive  curators,  Partsch,  Homes, 
Brezina,  and  Berwerth,  were  zealous  students  of  the  subject. 
Much  of  our  knowledge  of  meteorites  has,  therefore,  been 
acquired  through  studies  of  the  Vienna  collection.  The 
British  Museum  had  in  1807  four  meteorite  specimens  and 
in  1860,  sixty-eight.  It  comprises  at  the  present  time  rep- 
resentatives of  about  six  hundred  falls,  many  of  the  speci- 


METEORITE    COLLECTIONS  223 

mens  of  which  are  of  unique  interest  and  value.  As  with 
the  Vienna  collection  the  curators  of  the  British  Museum 
collection  have  been  leading  investigators,  as  the  names 
of  Flight,  Maskelyne,  and  Fletcher  will  show.  The  meteor- 
ite collection  of  the  Natural  History  Museum  of  Paris 
possessed  early  in  the  nineteenth  century  a  score  of  speci- 
mens which  had  increased  in  1860  to  sixty-four.  This  col- 
lection now  numbers  nearly  six  hundred  falls,  many  of  which 
are  of  great  importance.  The  long  connection  of  Meunier 
with  this  collection,  which  happily  still  continues,  has  been 
fruitful  of  rich  contributions  to  meteoritics.  The  Royal 
Natural  History  Museum  of  Berlin  early  received  the 
collection  of  Chladni  numbering  representatives  of  about 
fifty  falls  and  under  the  care  of  Rose,  Klein,  and  others  has 
kept  pace  with  other  important  collections  in  its  growth. 
Other  large  and  representative  collections  in  Europe  are 
to  be  found  in  Buda-Pesth,  Greifswald%  Stockholm,  Got- 
tingen,  Dorpat,  and  Strasburg.  Large  private  collections  are 
also  possessed  there  by  Prof.  Friedrichs  in  Vienna,  Marquis* 
de  Mauroy  in  Wassy,  France,  and  Max  Neumann  in  Gratz. 
In  the  United  States  collecting  of  meteorites  began  with 
the  preservation  at  Yale  College  in  1807  of  the  meteorites 
which  fell  at  Weston,  Connecticut,  in  that  year.  In  1810 
the  large  Gibbs  iron  weighing  nearly  a  ton  (1635  pounds) 
was  brought  from  Texas  after  much  hardship  and  difficulty. 
This  was  presented  to  the  Yale  collection  in  1835.  Other 
important  falls  have  been  added  to  the  collection  from  time 
to  time  and  it  now  includes  representatives  of  nearly  two 
hundred  and  fifty.  Harvard  University  obtained  speci- 
mens of  about  fifty  meteoric  falls  from  Prof.  J.  P.  Cooke 
but  gained  its  most  valuable  specimens  by  the  purchase  in 
1883  of  the  collection  of  Dr.  J.  Lawrence  Smith.  The  total 
number  of  falls  now  represented  in  the  Harvard  collection  is 
about  three  hundred.  A  collection  of  about  the  same  size  is 
possessed  by  Amherst  College,  its  acquisition  having  been 
due  chiefly  to  the  labors  of  Prof.  C.  U.  Shepard.  Large 
collections  of  meteorites  are  possessed  by  the  Natural  His- 
tory Museums  of  Washington,  New  York,  and  Chicago,  that 
of  the  last  city  at  the  Field  Museum  being  now  the  largest 


METEORITE    COLLECTIONS  225 

in  the  world  (Fig.  65).  This  collection  was  inaugurated  in 
1894  at  the  time  of  the  founding  of  the  Field  museum  by 
purchase  of  collections  from  George  F.  Kunz  and  Ward's 
Natural  Science  Establishment.  In  1912  the  private  collec- 
tion of  Prof.  Henry  A.  Ward  numbering  over  six  hundred 
falls  was  added  to  the  collection  and  thus  the  most  repre- 
sentative series  of  meteorites  in  the  world  was  secured. 
The  meteorite  collection  at  Washington  at  the  United  States 
National  Museum  has  been  gathered  since  1880.  Over  four 
hundred  falls  are  now  represented  in  this  collection  and 
among  them  are  the  unrivaled  Tucson  ring  and  the  historic 
Casas  Grandes.  The  American  Museum  of  Natural  History 
in  New  York  City  has  a  collection  representing  nearly  five 
hundred  falls  including  the  great  Cape  York  masses  and  the 
large  Willamette  iron.  There  are  small  collections  of 
meteorites  in  this  country  numbering  from  fifty  to  one 
hundred  and  fifty  falls  at  Adelbert  College,  Ohio,  the  Mil- 
waukee Public  Museum,  the  University  of  Minnesota,  the 
Academy  of  Sciences  of  Philadelphia,  and  the  Academy  of 
Sciences  at  St.  Louis.  At  the  Mexican  National  Museum 
and  School  of  Mines  in  the  City  of  Mexico  the  great  Mex- 
ican irons  of  Chupaderos,  Morito,  Zacatecas,  etc.,  are  pre- 
served, together  with  many  other  smaller  but  important 
meteorites.  At  Calcutta,  India,  a  large  collection  of  meteor- 
ites has  been  for  many  years  maintained,  its  growth  being 
favored  by  the  large  number  of  stone  meteorites  which  have 
fallen  in  India.  In  Japan,  Australia,  South  Africa,  and 
other  parts  of  the  world  meteorite  collections  are  gradually 
being  gathered  and  thus  facilities  are  rapidly  being  widely 
increased  for  the  preservation  and  study  of  these  bodies. 


TABLE  OF   METEORITIC 


GENERAL  CHARACTERS 


Species  Composit 


Non-magnetic  or  only  slightly  so  before  heating.      B.  B.  fuses     Pyrrhotite        FeS 
to  magnetic  globule.     When  roasted  in  the  open  tube  or  on 
charcoal  gives  the  odor  of  SO->  and  reddens  litmus  paper. 
Decomp.  by  HC1  and  HNO3.     Easily  soluble  in  HC1  with 
evolution  of  H2S.     Sol.  in  HNOs  with  evolution  NO-> 


Strongly  magnetic  before  heating: 

Gives  no  odor  on  roasting  nor  reddening  of  litmus  paper. 

Heated  with  magnesium  wire  in  a  closed  tube  and  moistened 
with  water  gives  the  disagreeable  odor  of  phosphuretted 
hydrogen.  Soluble  in  HC1  and  Aqua  regia.  Insol.  in 
copper  ammonium  chloride.  Treated  with  HNOs  or  dis- 
solved in  HC1  gives  yellow  ppt.  with  Am  MoO4.  Decomp. 
with  difficulty  bv  HNO3 


Schreibersite    (Fe,  Ni,  Co 


GENERAL  CHARACTERS 


SPECIFIC  CHARACTERS 


Reacts  for       Malleable 

nickel  Sol.  in  HC1  or  HNO3 


Nickel-iron       Fe+\i 


Kamacire 


Keu 


Usually  in  flexible  plates  which  fuse  on    Taenite 
thin     edges     B.  B.     Sol.     in     copper 
ammonium  chloride 


Fe,  N.+CY 
Fe  Ni+( 


Brittle.     Fuses  in  R.  F.  emitting  sparks.     Cohenite 
Decomposed  with  difficulty  by  con- 
cen.  HC1.     Sol.  in  copper  ammonium 
chloride 


(Fe,  Ni,  Cc 


Fine  powder  slowly  but  completely  soluble  in  HC1         Magnetite.       FegO 


Not  magnetic 
before  heating 

Impart  a 
green  color 
to  salt  of 
phosphorus 
or  borax 
bead 
(Chromium) 

Reacts  for  sulphur  when  roasted  in 
open  tube.  Becomes  magnetic  \\lun 
heated  in  R.  F.  Brittle.  Sol.  in 
HNOs  and  Aqua  Regia 

Daubreelite 

A  little  of  the  fine  powder  when  mixed 
with  an  equal  volume  of  Na2CO.j  and 
intensely  heated  on  charcoal  gives  a 
magnetic  mass.  Insol.  in  acid 

Chromite 

Soft.     Soils  the  fingers.  Very  refractorv.  Graphite 

Deflagrates  with  KNO3.     Use  equal  parts  mineral  and  KNO:i. 


RALS  WITH   METALLIC  LUSTRE 

;IBLK 


Color 

Sneak         .     Cleavage  and  Fracture 

Hard- 
ness 

Spec. 
Grav. 

Fusi- 
bility 

Crystalli- 
zation 

Bronze- 

(  iravish- 

Uneven 

4 

4.68- 

2-5-3 

Hexagonal 

yellow  to 

black 

4.82 

brown 

Tin-white, 
steel-^rav. 

Grayish- 
black 

Brittle 

6-5 

6.3- 

7.28 

2-5 

bronze- 

yellow 

Steel-gray 

Steel-gray 

Octahedral 
Cubic                      Hackly 

4-5 

7-3- 
7-5 

Isometric 

Steel-gray 

7.8c^ 

7.88 

Isometric 

Tin-white 
to  golden- 
yellow 

Isometric 

Tin-white, 
bronze- 
Yell  ovv 

5.5-6 

7-23- 
7.24 

Isometric 

Iron-hlack 

Black 

Parting 
octahedral.           Uneven 

6 

5.18 

Isometric 

Black 

Black 

One  direction 

5-01 

Massive 
Scaly 

Iron-hlack 
to  brownish 
black      . 

Dark 
brown 

Uneven 

5-5 

4.6 

Isometric 
U.  massive 

Iron-black 

Black 

Basal  (perfect) 

1-15 

2.20 

Hexagonal  Rh. 
Foliated 

GENERAL   INDEX 


Achondrites,  108,  198 
Aerolites,  197  • 
Aerolitics,  5 
Aerosiderites,  197 
Aerosiderolites,  197 
Allen,  E.  T.,  141,  176 
Aluminum,  113 

American  Museum  collection,  225 
Amherst  collection,  223 
Amorphous  carbon,  124 
Amphoterite,  198  . 
Analyses  of  anorthite,  168 

of  chromite,  165 

of  chrysolite,  186 

of  cohenite,  156 

of  gases,  191,  192,  194,  195,  196 

of  hedenbergite,  179 

of  insoluble  silicates,  175 

of  kamacite,  132 

of  orthorhombic  pyroxene,  173 

of  plagioclase,  169 

of  pyrrhotite,  145 

of  rhabdite,  155 

of  schreibersite,  153 

of  taenite,  134 

of  vein  material,  87 
Angrite,  198 
Anorthite,  167 
Ansdell,  G.,  124,  194 
Antimony,  116 
Apatite,  187 

Apparent  paths  of  meteors,  32 
Argon,  113 
Armored  surfaces,  86 
Arsenic,  116 
Asiderites,  197 
Asmanite,  162 
Ataxites,  98,  203 
Atmospheric  resistance,  18 
Augite,  105,  1 80 
Average  composition  of  meteorites,  216 

Balkeneisen,  130 
Ball,  Robert,  33 
Bandeisen,  133 
Barium,  116 
Barnard,  E.  E.,  212 
Barringer,  D.  M.,  25 
Bell-shaped  meteorites,  70 
Bent  figures,  91 


Berlin  collection,  223 

Berwerth,  F.,  5,  35,  96,  98,  99,  178,  181, 

184,   187,  222 

Berzelius,  J.  J.,  124 
Bismuth,  116 
Blake,  W.  P.,  74 

Borgstrom,  L.  H.,  21,  83,  139,  150,  165 
Breunnerite,  166 

Brezina,  A.,  77,  83,  89,  101,  108,  no, 
in,  121,  122,  126,  130,  131,  139, 

141,    143,    149,    150,    171,    198,    222, 

223 

Brezina  lamellae,  100,  150 
British  Museum  collection,  222 
Bronzite,  171 
Bustite,  198 

Calcium,  113 

Carbon,  113,  124 

Carbon  dioxide,  191,  196 
monoxide,  191,  196 

Chamberlin,  R.  T.,  195 
T.  C.,  211,  212 

Chassignite,  198 

Chondri    102,  127 

Chondrites,  199 

Chondritic  structure,  102,  206 

Chladnite,  171,  198 

Chlorine,  113,  159 

Chromite,  164 

Chromium,  113 

Chrysolite,  103,  181 

Classification,  197 

Cliftonite,  122 

Clinoenstatite,  176 

Clinohypersthene,  176 

Cobalt,  114 

Codonoid  shape,  70 

Cohen,  E.,  50,  68,  79,  88,  89,  90,  120, 
123,  126,  134,  140,  147,  149,  151, 
152,  159,  160,  162,  172,  174,  175, 
177,  178,  179,  1 86,  1 88 

Cohenite,  155 

Column  shape,  74 

Combs,  94 

Comets,  208 

Cone-shape,  60 

Coon  Butte,  23 

Copper,  114 

Cricoid  shape,  74 


227 


228 


GENERAL   INDEX 


Crust  of  iron  meteorites,  78 

of  stone  meteorites,  82 

zones,  82 
Cubic  meteorites,  97 

Daily  falls,  40 

Darwin,  G.  H.,  211 

Daubree,  A.,  51,  52,  105,  152,  157,  162, 

187,  197 

Daubreelite,  144,  146 
Davison,  J.  M.,  136 
Derby,  O.  A.,  120,  152 
Dewar,  J.,  124,  194 
Diallage,  177 
Diamond,  118 
Diopside,  178 
Direct  motion,  43 
Disruptive  forces,  212 
Distribution  of  showers,  50 
Dyslytite,  147 

Eastern  hemisphere,  meteorites  of,  35 

Edmondsonite,  133 

Eisenglas,  79 

Elements,  113 

Enstatite,  104,  171 

Etching  figures,  127 

Eukrites,  109,  198 

Eutectic,  137 

Faulting,  90 

Feldspar,  166 

Ferrous  chloride,  157 

Field  Museum,  223 

Fletcher,  L.,  122,  126,  137,  165 

Flight,  W.,  193,  223 

Foote,  A.  E.,  119 

Foote  Mineral  Co.,  128 

Forms  of  meteorites,  60 

Forsterite,  181 

Front  side  of  meteorites,  63 

Fiilleisen,  136 

Gases,  190 

General  characters,  I 

Geographical  distribution,  34 

Gilbert,  G.  K.,  25 

Glanzeisen,  147 

Glass   105,  190 

Gnathoid  shape,  75 

Gold,  116 

Graham,  T.,  191 

Grahamite,  201 

Graphite,  123,  144,  194 

Haidinger,  W.,  45,  64,  74,  121,  140 
Harnischflache,  86 
Harvard  collection,  223 


Hedenbergite,  179 
Helium,  114 
Herschel,  21 
Hexahedrites,  98,  203 
Hobbs,  W.  H.,  68 
Hourly  falls,  41 
Howardites,  35,  199 
Huntington,  O.  W.,  97,  119,  122 
Hussak,  E.,  156,  164 
Hydrocarbons,  188 
Hydrogen,  114,  191 
Hypersthene,  171 

Injuries. caused  by  meteorites,  28,  29 
Iridium,  114 
Iron,  meteoric,  114 
terrestrial,  206 

Jaw-shaped  meteorites,  75 

Kamacite,  93,  129,  130 

Kunz,  Geo.  F.,  65,  no,  118,  119,  149, 

157,  183,  225 

Labradorite,  169 

Lamprite,  147,  155 

Lane,  A.  C.,  177 

Lang,  V.  v.,  167,  171,  172,  174 

Lawrencite,  157 

Lead,  116 

Linck,  G.,97 

Lithosiderites,  201 

Liversidge,  A.,  70,  72,  116 

Lockyer,  J.  N.,  210 

Lodranite,  201 

Lowell,  P.,  44 

Magnesium,  114 

Magnetite,  163 

Manganese,  114 

Mallet,  J.  W.,  191 

Maskelyne,  N.  S.,  5,  138,  139,  162,  178, 

ivyr    ,19,7'"3 
Maskelynite,  105,  170 

Merrill,  G.  P.,  139,  188 

Mesosiderites,  no,  201 

Meteorin,  133 

Meteorite  collections,  220 

Meteor  Crater,  23,  25 

Meteorite  showers,  46,  50 

Meteoritic  dust,  219 

Meteoritic  hypothesis,  210 

Meteoritics,  5 

Methods  of  etching,  127 

Meunier,  S.,  88,   140,    147,    151,    163, 

197,  223 
Michel,  H.,  169 
Minerals  of  meteorites,  116 


GENERAL  INDEX 


229 


Moissan,  H.,  120,  121,  157 
Moissanite,  157 
Monoclinic  pyroxenes,  177 
Monthly  falls,  38 
Monticellite,  188 
Moon,  25,  207 
Moulton,  F.  R.,  32 

Naming  of  meteorites,  4 
Neumann,  J.  G.,  96,  97 
Neumann  lines,  96 
Newton,  H.  A.,  44,  m,  208,  213 
Ngawite,  200 
Nickel,  3,  114 
Nickel-iron,  105,  124 
Niessl,  v.,  19 
Nitrogen,  115,  191 

Number  of  individuals  in  showers,  49 
of  falls,  4 

Observation  of  metec  rs,  29 
Octahedral  figures,  92 
Octahedrites,  202 
Oldhamite,  138 
Oligoclase,  169 

Ophitic  structure,  109,  no,  167 
Orbits  of  meteorites,  213 
Origin  of  chondri,  213 

of  meteorites,  205 

of  showers,  50,  52 

of  veins,  88 
Ornansite,  200 

Orthorhombic  pyroxenes,  171 
Orvinite,  200 
Osbornite,  139 
Ostracoid  shape,  69 
Oxygen,  115 

Palladium,  115 

Pallasites,  201,  202 

Paris  collection,  223 

Partsch,  P.,  121,  126,  222 

Partschite,  147 

Patton,  H.  B.,  177 

Peltoid  shape,  69 

Phenomena  of  falling  meteorites,  7 

Phosphornickeleisen,  147 

Phosphorus,  115 

Physical  effects,  217 

Pickering,  W.  H.,  40,  44,  213 

Piddingtonite,  171 

Fittings,  63 

Plagioclase,  105,  169 

Platinum,  115 

Plessite,  93,  130,  136 

Potassium,  115 

Pyroxene,  171 

Pyrrhotite,  83,  140 


Quantitative  classification,  204 
Quartz,  161 

Radium,  115 

Ramsay,  W.,  83 

Rath,  G.  v.,  64,  in 

Rear  side  of  meteorites,  63 

Reichenbach,  C.  v.,  79,  88,  89,  93,  no, 

D  •  ;"'  I2g^3o,  131,  136,  H3 
Reichenbach  lamellae,  100,  143 
Relation  of  meteorites  to  comets,  208, 

213 

Retrograde  motion,  43 
Rhabdite,  147 
Ring  shape,  74 
Rinne,  F.,  95,  138 
Rodite,  198 
Rose,  G.,  in,  121,  122,  140,  142,  161, 

167,  180,  182,  183,  198,  223 
Ruthenium,  115 

Saturn,  211 

Schiaparelli,  J.  V.,  19,  213 

Schreibersite,  144,  147 

Secondary  crust,  84 

Shell  shape,  69 

Shepard,  C.  U.,  5,  165,  188,  223 

Shepardite,  171 

Shergottite,  109,  199 

Shield  shape,  68 

Showers,  46 

Siderites,  197 

Siderolites,  201 

Siderophyr,  201 

Siemaschko,  J.  v.,  126 

Silicon,  115 

Size  of  meteorites,  54 

Slickensided  surfaces,  89 

Smith,  J.  Lawrence,  123,  142,  146,  152, 

164,  189,  223 
Smith,  S.  W.  J.,  133 
Sodium,  115 
Soluble  salts,  160 
Sound  phenomena,  20 
Sporadosiderites,  197 
Strontium,  116 
Structure  of  iron-stone  meteorites,  101 

of  meteorites,  92 

of  stone  meteorites,  102 
Styloid  shape,  74 
Sulphur,  116 
Syssiderites,  197 

Tadjerite,  200 
Taenite,  93,  129,  133 
Tassin,  W.,  139,  163 
Terrestrial  relations,  214 
Tesseral  octahedrite,  95 


230 


GENERAL   INDEX 


Times  of  fall,  37 

Tin,  116 

Titanium,  116 

Travers,  M.  W.,  196 

Tridymite,  162 

Troilite,  140 

Tschermak,  G.,  64,  82,  83,  86,  88,  104, 
105,  106,  107,  108,  109,  112,  143, 
149,  167,  170,  171,  179,  180,  184, 
185,  188,  198 

United  States  National  Museum  Col- 
lection, 225 

Vanadium,  116 

Veins,  85 

Velocity  of  meteorites,  19,  22,  44 

Victorite,  171 

Vienna  collection,  222 


Wadsworth,  M.  E.,  108 

Wahl,  W,  176,  177 

Ward,  H.  A.,  55,  225 

Warmth  of  meteorites,  20,  27 

Water,  160 

Weinbergerite,  181 

Weinschenk,    E.,    120,    123,    149,    156, 

162 

Weisbach,  A.,  172 
Western    hemisphere,    meteorites    of, 

Widmanstatten  figures,  92,  127 
Winchell,  N.  H.,  171 
Wohler,  F.,  124 
Wright,  A.  W.,  191,  193 

Yale  Collection,  223 
Yearly  falls,  37 
Young,  C.  A.,  217 


INDEX  OF   METEORITES 


Adargas,  57,  5§ 

Admire,  48,  165,  187 

Agen,  48 

Agram,  see  Hraschina 

Alais,  161,  189 

Albacher  Miihle,  see  Bitburg 

Albareto,  140 

Aleppo,  48 

Alexejewka,  see  Bachmut 

Alfianello,  105 

Algoma,  68 

Allegan,  139,  166,  195 

Anderson,  187 

Angra  dos  Reis,  109,  116,  124,  180,  184, 

188 

Arispe,  49 
Aubres,  139 
Aussun,  29,  176 

Babb's  Mill,  74,  203 

Bachmut,  202 

Bacubirito,  55,  58,  76,  91 

Ballinoo,  150 

Bandong,  49 

Barbotan,  29,  46,  48 

Barratta,  49 

Bath  Furnace,  66,  67 

Beaconsfield,  see  Cranbourne 

Bear  Creek,  146 

Benares,  29 

Bendego,  56,  58,  132,  145,  155,  156,  164, 

172 

Bethany,  48,  50,  95 
Bingera,  98,  126 

Bischtiibe,  49,  135,  154,  162,  168 
Bishopville,  78,  85,  no,  139,  161,  171, 

173,  174,  176 
Bitburg,  202 

Bjurbole,  58,  83,  146,  166 
Blansko,  49 
Bluff,  85,  87,  ill 
Bohumilitz,  154 

Bolson  di  Mapimi,  see  Coahuila 
Boogaldi,  70,  71,  72,  73,  116 
Borgo  San  Donino,  48 
Borkut,  127 

Braunau,  14,  20,  28,  49,  66,  149 
Breitenbach,  see  Steinbach 
Bremervorde,  49 
Brenham,  48,  101,  185,  186,  187 


Bridgewater,  90 

Bustee,  78,  no,  138,  172,  174,  177,  178 

Butsura,  46,  49,  70 

Cabin  Creek,  13,  28,  59,  62,  65,  79 

Caille,  135,  143,  162 

Cambria,  154 

Canyon  Diablo,  23,  48,  52,  70,  119,  120, 

121,  126,  132,  135,  144,  154,  155, 

156,  157,  160,  163,  166 
Cape  Girardeau,  175 
Cape  Iron,  159,  203 
Cape  York,  54,  57,  58,  220,  225 
Carcote,  120,  152 
Carlton,  66,  90,  91,  148 
Carthage,  164 

Casas  Grandes,  57,  58,  135,  154,  225 
Castalia,  46 
Castine,  5 
Chail,  48 

Chantonnay,  85,  88 
Charcas,  58,  135,  162  » 

Charlotte,  70,  79,  192 
Charwallas,  160 

Chassigny,  108, 1 1 1 , 1 24, 1 8 1 , 1 84, 1 87, 190 
Chateau  Renard,  105 
Chulafinnee,  123 
Chupaderos,  49,  55,  134,  225 
Clarac,  see  Aussun 
Cleveland,  66,  143 

Coahuila,  48,  50,  97,  141,  154,  164,  166 
Cold  Bokkeveld,  46,  48,  161,  192 
Collescipoli,  188 
Concepcion,  see  Adargas 
Copiapo,  173,  174,  202 
Cosby  Creek,  49,   122,    123,    134,    135, 

142,  146,  154,  162 
Costilla,  66 

Crab  Orchard,  49,  102,  in,  160,  162,  168 
Cranbourne,  57,  58,  123,  135,  146,  154, 

155,  162,  193 
Cronstadt,  48 
Cynthiana,  176 

Danville,  146 

Deep  Springs,  159 

Dehesa,  120 

De  Sotoville,  see  Tombigbee  River 

Descubridora,  90,  91 

Dhurmsala,  48,  105,  106,  194 


231 


232 


INDEX   OF   METEORITES 


Dona  Inez,  163 
Drake  Creek,  49 
Durala,  70 

Eagle  Station,  183,  187 

Elbogen,  154,  220 

El  Morito,  56,  58,  65,  225 

Ensisheim,  165,  220 

Estherville,  21,46,48,  in,  127, 142, 176 

Estacado,  195 

Farmington,  21,  88,  89,  142,  190 

Fisher,  171 

Forest,  46,  48 

Forsyth,  159 

Fort  Duncan,  98 

Frankfort,  168 

Futtehpore,  48 

Gargantillo,  see  Tomatlan 

Gibbs,  see  Red  River 

Glorieta,  49,  91,  132,  134,  151,  154,  162 

Gnadenfrei,  176 

Goalpara,  63,  126,  185,  188 

Gopalpur,  127,  169 

Grazac,  48 

Great  Nama  Land,  see  Bethany 

Greenbrier  County,  126,  165 

Grossliebenthal,  169,  175 

Griineberg,  142 

Hainholz,  no,  in,  160,  176 

Harrison  County,  49 

Hessle,  10,  46,  48,  in,  169,  189,  190 

Hex  River  Mts.,  75,  98,  149,  155,  162 

Holbrook,  46,  48,  49,  59 

Holland's  Store,  98,  149 

Homestead,  16,  20,  46,  47,  48,  104,  in, 

192,  193 

Honolulu,  125,  152 
Hraschina,  10,  20,  49,  92,  154 
Hvittis,  21,  139,  169,  174 

Ibbenbiihren,  109,  171,  174 

Ilimae,  134,  143,  148 

Imilac,  48,  126,  1 86,  187,  202 

Inca,  48 

Indarch,  139 

Indian  Valley,  98,  149 

Ivanpah,  162 

amestown,  91 

arnyschewa,  see  Pawlodar 

elica,  48,  146 

ewell  Hill,  143 

onzac,  48,  64,  109,  167 

uncal,  80 

uvinas,  109,  in,  140, 167, 168, 179, 180 


Kendall  County,  120,  154 

Kenton  County,  135 

Kesen,  48 

Khairpur,  9,  46,  48 

Khetree,  48 

Kilbourn,  22 

Killeter,  48 

Klein-Wenden,  166 

Knyahinya,    15,  20,  23,  46,  48,  49,  58, 

103,  213 

Kodaikanal,  180,  187,  202 
Kokstad,  75,  162 
Krahenberg,  20 
Krasnojarsk,  135,  182,  186,  187,  201 

L'Aigle,  46,  48,  49,  81,  85,  161,  166,  222 

Lance,  10,  49 

Lancon,  88 

Laurens  County,  157 

Lenarto,  191 

Lick  Creek,  98,  126,  159 

Limerick,  46 

Lime  Creek,  see  Limestone  Creek 

Limestone  Creek,  155,  157,  160,  162 

Linville,  203 

Llano  del  Inca,  176,  177 

Locust,  162 

Lodran,  109,  165, 166,  172,  174,  182,  186 

Long  Island,  58,  66,  89 

Losttown,  49 

Luotolaks,  180 

Macao,  29,  46,  48 

Madrid,  48,  170 

Magura,  58,  90,  120,  121,  123,  132,  133, 

135,  142,  151,  154,  155,  156, 162,  192 
Manbhoom,  48,  in 
Manegaum,  109,  no,  171,  172,  174 
Marion,  49,  160 
Marjalahti,  154,  165,  166,  187 
Massing,  29,  172 
Mazapil,  14,  28,  123,  208 
Medwedewa,  see  Krasnojarsk 
Merceditas,  142 

Mezo-Madarasz,  48,  103,  107,  127,  190 
Middlesbrough,  21,  125 
Mighei,  176 

Mincy,  102,  no,  183,  186 
Misshof,  172 

Misteca,  134,  135,  149,  162 
Mocs,  7,  20,  46,  48,  49,  81,  82,  83,  85,  86, 

172,  179,  194 
Modoc,  48,  8 1 
Molina,  175 
Monte  Milone,  48 
Mordvinovka,  125 
Morito,  see  El  Morito 
Morristown,  139,  160,  168 


INDEX  OF   METEORITES 


233 


Mount  Joy,  92,  154 
Mount  Vernon,  166 
Muchachos,  see  Tucson 
Murphy,  98 

Nagaya,  160,  161,  189 
Nakhla,  29,  177,  178 
Narraburra,  116,  150 
Nedagolla,  203 
Nenntmannsdorf,  98,  146 
Nerft,  125,  152 
Ness  County,  48 
Netschaevo,  202 
New  Concord,  13,  46,  48,  191 
N'Goureyma,  68,  203 
Nocoleche,  146 

Nowo  Urei,  109,  118,  178,  180 
Nulles,  48 

Ochansk,  see  Tabory 

Orgueil,  20,  48,  51,  161,  166,  189 

Orvinio,  10,  85,  87 

Pallas,  see  Krasnojarsk 

Parnallee,  127,  190,  192 

Pawlodar,  187 

Penkarring  Rock,  see  Youndegin 

Petersburg,  168,  180 

Pillistfer,  29,  46 

Ploschkowitz,  48 

Prambanan,  79 

Pnmitiva,  203 

Pultusk,  20,  46,  48,  49,  85,  88,  in,  161, 

176,  192,  194,  213 
Puquios,  90,  91 

Quenggouk,  15 

Quesa,  89 

Quinn  Canyon,  58,  65,  164 

Rasgata,  162 
Red  River,  58,  93,  192 
Renazzo,  105,  m,  127 
Richmond,  142,  176 
Rittersgriin,  see  Steinbach 
Rochester,  52,  176 
Roda,  124,  176 
Rokicky,  187,  202 
Rowton,  14,  146,  193 

Sacramento,  89 

St.  Genevieve  County,  160 

St.  Michel,  21,  83 

Saintonge,  see  Jonzac 

Saline,  152 

Salt  Lake  City,  175 

San  Emigdio,  176 

San  Gregorio,  see  El  Morito 


Santa  Rosa,  149,  155 

Sao  Juliao,  154,  159,  162 

Sarepta,  151 

Sauguis,  8 

Schwetz,  162,  164 

Scottsville,  98 

Seelasgen,  146,  149,  151,  155 

Segowlee,  48 

Sewrukof,  166 

Shalka,  no,  124,  166,  171,  173,  174 

Shergotty,  109,  163,  170,  179,  180 

Shingle  Springs,  192,  203 

Siena,  48,  in 

Sierra  de  Chaco,  see  Vaca  Muerta 

Sierra  di  Deesa,  see  Copiapo 

Siratik,  203 

Smith  Mountain,  157 

Smith  ville,  49,  122 

Sokobanja,  8,  48,  146,  176 

Stalldalen  49,  85,  87,  176 

Stannern  46,  48,  109,  112,  168,  180 

Staunton,  49,  126,  132,  135,  143,  191 

Steinbach,  49,  146,  162,  172,  174 

Summit,  98 

Tabory,  7,  48,  89,  126 

Tadjera,  88,  176 

Tazewell,  146,  150,  154,  157,  192 

Tennasilm,  145,  169 

Tieschitz,  127 

Toluca,  48,  52,  76,  91,  99,  120,  123,  132, 

134,  146,  148,  151,  154,  160,  161, 

162,  163,  169,  195 
Tomatlan,  48 
Tombigbee  River,  98,  154 
Tomhannock  Creek,  in 
Tonganoxie,  126 
Toulouse,  48 
Trenton,  49,  143 
Tucson,  49,  74,  81,  203,  225 

Vaca  Muerta,  in,  146,  162,  168 
Victoria  West,  143,  202 

Waconda,  169,  176 

Warrenton,  12 

Welland,  126,  132,  135,  136 

Weston,  n,  20,  46,  48,  in,  192 

Wichita  County,  134,  135,  144, 155,  156 

Willamette,  55,  58,  65,  225 

Wold  Cottage,  1 1 1 

Youndegin,  49,  81,  122 

Zabrodje,  169 

Zacatecas-,  58,  154,  202,  225 

Zavid,  184 

Zsadany,  49,  152,  176 


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r^zw        u-»J§ssa-i. 

i.. 


